feat(domain,application,backend,app-tauri,frontend): lot utilisateur #328 #329 #330 #331 — section plugins projet, erreurs menus plugin visibles, refresh auto des pages, droplist agents (QA verte)

Lot en un seul commit: les quatre tickets partagent les mêmes fichiers
(événements domaine/DTO, ProjectPluginsPanel, useProjectPlugins) — une
séparation par hunks aurait risqué des états intermédiaires non
compilables (convention lot des batches #310-#313, #315 et #325-#326).

#328 — section dédiée plugins dans Paramètres du projet:
- frontend: ProjectPluginsPanel intégré à ProjectSettingsPanel
  (Panneaux > Paramètres du projet) — activation/désactivation par
  plugin avec état actif/inactif explicite par projet, distinct de
  l'assignation agents/skills/tools
- domaine: événement ProjectPluginSettingsChanged publié par
  SetProjectPluginEnabled, MutateAgentPluginSkill et
  MutateAgentPluginTool après persistance de .ideai/project-plugins.json
  (application + backend + DTO camelCase, test dto.rs)

#329 — les menus plugin qui échouent ne sont plus muets:
- usePluginMenus: dispatcher strict (runCommandStrict) pour les
  commandes réellement enregistrées au lieu du dispatcher laxiste qui
  journalisait et avalait les rejets — rendait les échecs d'ouverture
  de fenêtres natifs invisibles pour l'hôte de menus
- le no-op SDK historique (commande déclarée sans handler) est préservé
- échec remonté à l'hôte via commandError/clearCommandError (journal
  console + état exposé); test window_usecases adapté à un plugin
  installé
- le correctif côté SDK/GitPlugin vit dans le projet GitPlugin (son
  commit/merge local y est fait, hors périmètre de ce dépôt)

#330 — refresh automatique des pages:
- frontend/domain: typage des événements pluginEnabled,
  pluginDisabled (restartRequired), pluginUninstalled
  (restartRequired), pluginLoadFailed et projectPluginSettingsChanged
- useProjectPlugins et PluginRuntimeProvider: souscription
  onDomainEvent — refresh sur changement catalogue global ou sur
  projectPluginSettingsChanged du projet courant; gardes
  révision/projet contre les réponses obsolètes
- useProjectAgents: refresh auto quand un agent est ajouté au projet;
  ProjectsView et AgentsPanel suivent (erreur de rafraîchissement
  affichée avec bouton Réessayer)

#331 — droplist agents des cellules:
- SmallDropdown: liste bg-overlay + bordure border-strong (plus de
  fond blanc hors thème), hover/focus bg-raised, sélection
  bg-primary/15, disabled text-faint opacity-60, role=combobox
- LayoutGrid: sélecteur d'agent des cellules migré du <select> natif
  vers SmallDropdown (mêmes libellés Terminal/visible
  ailleurs/arrière-plan)

QA verte réelle sur les quatre lots (tests ciblés + exécution).
sdk/IdeaSDK: contenu modifié non committable ici (pointeur inchangé).
Aucun push.

crates/app-tauri/tests/dto.rs

@@ -206,6 +206,21 @@ fn domain_event_dto_is_tagged_and_camel_case() {
     );
 }
 
+#[test]
+fn project_plugin_settings_changed_event_is_tagged_and_camel_case() {
+    let pid = ProjectId::from_uuid(Uuid::from_u128(328));
+    let dto = DomainEventDto::from(&DomainEvent::ProjectPluginSettingsChanged { project_id: pid });
+    let value = serde_json::to_value(dto).unwrap();
+
+    assert_eq!(
+        value,
+        json!({
+            "type": "projectPluginSettingsChanged",
+            "projectId": pid.to_string(),
+        })
+    );
+}
+
 #[test]
 fn domain_event_dto_maps_agent_launched() {
     let aid = AgentId::from_uuid(Uuid::nil());

crates/application/src/project_plugin.rs

@@ -4,10 +4,11 @@ use std::collections::HashSet;
 use std::sync::Arc;
 
 use domain::{
-    AgentContextStore, AgentId, AgentPluginAssignments, MarkdownDoc, PluginId, PluginManifest,
-    PluginManifestValidator, PluginMcpServerId, PluginMcpServerSpec, PluginPackageStore,
-    PluginRegistryStore, PluginSkillId, PluginSkillRef, PluginStoreError, PluginToolRef, Project,
-    ProjectPluginActivation, ProjectPluginSettings, ProjectPluginSettingsStore,
+    AgentContextStore, AgentId, AgentPluginAssignments, DomainEvent, EventBus, MarkdownDoc,
+    PluginId, PluginManifest, PluginManifestValidator, PluginMcpServerId, PluginMcpServerSpec,
+    PluginPackageStore, PluginRegistryStore, PluginSkillId, PluginSkillRef, PluginStoreError,
+    PluginToolRef, Project, ProjectPluginActivation, ProjectPluginSettings,
+    ProjectPluginSettingsStore,
 };
 use serde::{Deserialize, Serialize};
 
@@ -292,6 +293,7 @@ impl ListProjectPluginSettings {
 pub struct SetProjectPluginEnabled {
     store: Arc<dyn ProjectPluginSettingsStore>,
     packages: Arc<dyn PluginPackageStore>,
+    events: Arc<dyn EventBus>,
 }
 
 impl SetProjectPluginEnabled {
@@ -300,8 +302,13 @@ impl SetProjectPluginEnabled {
     pub fn new(
         store: Arc<dyn ProjectPluginSettingsStore>,
         packages: Arc<dyn PluginPackageStore>,
+        events: Arc<dyn EventBus>,
     ) -> Self {
-        Self { store, packages }
+        Self {
+            store,
+            packages,
+            events,
+        }
     }
 
     /// Persists activation. Enabling requires a currently installed plugin;
@@ -336,6 +343,10 @@ impl SetProjectPluginEnabled {
                 .push(ProjectPluginActivation { plugin_id, enabled }),
         }
         self.store.save(&project.root, &settings).await?;
+        self.events
+            .publish(DomainEvent::ProjectPluginSettingsChanged {
+                project_id: project.id,
+            });
         Ok(settings)
     }
 }
@@ -354,6 +365,7 @@ pub struct MutateAgentPluginSkill {
     store: Arc<dyn ProjectPluginSettingsStore>,
     contexts: Arc<dyn AgentContextStore>,
     resolver: Arc<ProjectPluginResolver>,
+    events: Arc<dyn EventBus>,
 }
 
 impl MutateAgentPluginSkill {
@@ -363,11 +375,13 @@ impl MutateAgentPluginSkill {
         store: Arc<dyn ProjectPluginSettingsStore>,
         contexts: Arc<dyn AgentContextStore>,
         resolver: Arc<ProjectPluginResolver>,
+        events: Arc<dyn EventBus>,
     ) -> Self {
         Self {
             store,
             contexts,
             resolver,
+            events,
         }
     }
 
@@ -412,6 +426,10 @@ impl MutateAgentPluginSkill {
             _ => {}
         }
         self.store.save(&project.root, &settings).await?;
+        self.events
+            .publish(DomainEvent::ProjectPluginSettingsChanged {
+                project_id: project.id,
+            });
         Ok(settings)
     }
 }
@@ -421,6 +439,7 @@ pub struct MutateAgentPluginTool {
     store: Arc<dyn ProjectPluginSettingsStore>,
     contexts: Arc<dyn AgentContextStore>,
     resolver: Arc<ProjectPluginResolver>,
+    events: Arc<dyn EventBus>,
 }
 
 impl MutateAgentPluginTool {
@@ -430,11 +449,13 @@ impl MutateAgentPluginTool {
         store: Arc<dyn ProjectPluginSettingsStore>,
         contexts: Arc<dyn AgentContextStore>,
         resolver: Arc<ProjectPluginResolver>,
+        events: Arc<dyn EventBus>,
     ) -> Self {
         Self {
             store,
             contexts,
             resolver,
+            events,
         }
     }
 
@@ -483,6 +504,10 @@ impl MutateAgentPluginTool {
             _ => {}
         }
         self.store.save(&project.root, &settings).await?;
+        self.events
+            .publish(DomainEvent::ProjectPluginSettingsChanged {
+                project_id: project.id,
+            });
         Ok(settings)
     }
 }
@@ -550,16 +575,82 @@ mod tests {
     use super::*;
     use async_trait::async_trait;
     use domain::{
-        ContentHash, LocalPath, PluginActivationScope, PluginCapability, PluginContributionSet,
-        PluginInstallSource, PluginLifecycleState, PluginManifestBytes, PluginManifestError,
-        PluginMcpServerContribution, PluginPackageRef, PluginRegistry, PluginRegistryEntry,
-        PluginTrustLevel, PluginVersion, ProjectPath, RelativePath, RemovalOutcome,
-        StagedPluginPackage,
+        Agent, AgentManifest, AgentOrigin, ContentHash, LocalPath, PluginActivationScope,
+        PluginCapability, PluginContributionSet, PluginInstallSource, PluginLifecycleState,
+        PluginManifestBytes, PluginManifestError, PluginMcpServerContribution, PluginPackageRef,
+        PluginRegistry, PluginRegistryEntry, PluginTrustLevel, PluginVersion, ProfileId,
+        ProjectPath, RelativePath, RemoteRef, RemovalOutcome, StagedPluginPackage,
     };
     use std::sync::Mutex;
 
     struct MemorySettings {
         settings: Mutex<ProjectPluginSettings>,
+        fail_save: bool,
+    }
+
+    #[derive(Clone, Default)]
+    struct SpyEvents(Arc<Mutex<Vec<DomainEvent>>>);
+
+    impl SpyEvents {
+        fn events(&self) -> Vec<DomainEvent> {
+            self.0.lock().unwrap().clone()
+        }
+    }
+
+    impl EventBus for SpyEvents {
+        fn publish(&self, event: DomainEvent) {
+            self.0.lock().unwrap().push(event);
+        }
+
+        fn subscribe(&self) -> domain::EventStream {
+            Box::new(std::iter::empty())
+        }
+    }
+
+    struct FakeContexts;
+
+    #[async_trait]
+    impl AgentContextStore for FakeContexts {
+        async fn read_context(
+            &self,
+            _project: &Project,
+            _agent: &AgentId,
+        ) -> Result<MarkdownDoc, domain::StoreError> {
+            Ok(MarkdownDoc::new("# Agent"))
+        }
+
+        async fn write_context(
+            &self,
+            _project: &Project,
+            _agent: &AgentId,
+            _md: &MarkdownDoc,
+        ) -> Result<(), domain::StoreError> {
+            Ok(())
+        }
+
+        async fn load_manifest(
+            &self,
+            _project: &Project,
+        ) -> Result<AgentManifest, domain::StoreError> {
+            let agent = Agent::new(
+                agent_id(),
+                "Dev",
+                "agents/dev.md",
+                ProfileId::from_uuid(uuid::Uuid::from_u128(2)),
+                AgentOrigin::Scratch,
+                false,
+            )
+            .unwrap();
+            Ok(AgentManifest::new(1, vec![domain::ManifestEntry::from_agent(&agent)]).unwrap())
+        }
+
+        async fn save_manifest(
+            &self,
+            _project: &Project,
+            _manifest: &AgentManifest,
+        ) -> Result<(), domain::StoreError> {
+            Ok(())
+        }
     }
 
     #[async_trait]
@@ -576,6 +667,9 @@ mod tests {
             _project_root: &ProjectPath,
             settings: &ProjectPluginSettings,
         ) -> Result<(), domain::StoreError> {
+            if self.fail_save {
+                return Err(domain::StoreError::Io("save failed".to_owned()));
+            }
             *self.settings.lock().unwrap() = settings.clone();
             Ok(())
         }
@@ -684,6 +778,17 @@ mod tests {
         ProjectPath::new("/project").unwrap()
     }
 
+    fn project() -> Project {
+        Project::new(
+            domain::ProjectId::from_uuid(uuid::Uuid::from_u128(328)),
+            "Plugin project",
+            project_root(),
+            RemoteRef::Local,
+            0,
+        )
+        .unwrap()
+    }
+
     fn manifest(auto_start: bool) -> PluginManifest {
         PluginManifest {
             idea_plugin_manifest_version: 1,
@@ -769,6 +874,7 @@ mod tests {
         ProjectPluginResolver::new(
             Arc::new(MemorySettings {
                 settings: Mutex::new(settings),
+                fail_save: false,
             }),
             Arc::new(MemoryPackages {
                 packages: vec![PluginPackageRef {
@@ -869,4 +975,111 @@ mod tests {
             .unwrap()
             .is_empty());
     }
+
+    #[tokio::test]
+    async fn project_plugin_activation_publishes_change_after_successful_save() {
+        let store = Arc::new(MemorySettings {
+            settings: Mutex::new(ProjectPluginSettings::default()),
+            fail_save: false,
+        });
+        let packages = Arc::new(MemoryPackages {
+            packages: vec![PluginPackageRef {
+                plugin_id: Some(plugin_id()),
+                root: "/plugins/unity".to_owned(),
+            }],
+            app_data_dir: None,
+        });
+        let events = SpyEvents::default();
+        let use_case = SetProjectPluginEnabled::new(store, packages, Arc::new(events.clone()));
+        let project = project();
+
+        use_case
+            .execute(project.clone(), plugin_id(), true)
+            .await
+            .unwrap();
+
+        assert_eq!(
+            events.events(),
+            vec![DomainEvent::ProjectPluginSettingsChanged {
+                project_id: project.id,
+            }]
+        );
+    }
+
+    #[tokio::test]
+    async fn project_plugin_activation_does_not_publish_when_save_fails() {
+        let store = Arc::new(MemorySettings {
+            settings: Mutex::new(ProjectPluginSettings::default()),
+            fail_save: true,
+        });
+        let packages = Arc::new(MemoryPackages {
+            packages: vec![PluginPackageRef {
+                plugin_id: Some(plugin_id()),
+                root: "/plugins/unity".to_owned(),
+            }],
+            app_data_dir: None,
+        });
+        let events = SpyEvents::default();
+        let use_case = SetProjectPluginEnabled::new(store, packages, Arc::new(events.clone()));
+
+        let error = use_case
+            .execute(project(), plugin_id(), true)
+            .await
+            .unwrap_err();
+
+        assert_eq!(error.code(), "STORE");
+        assert!(events.events().is_empty());
+    }
+
+    #[tokio::test]
+    async fn project_plugin_assignment_publishes_change_after_successful_save() {
+        let store = Arc::new(MemorySettings {
+            settings: Mutex::new(settings(true, Vec::new())),
+            fail_save: false,
+        });
+        let packages = Arc::new(MemoryPackages {
+            packages: vec![PluginPackageRef {
+                plugin_id: Some(plugin_id()),
+                root: "/plugins/unity".to_owned(),
+            }],
+            app_data_dir: None,
+        });
+        let resolver = Arc::new(ProjectPluginResolver::new(
+            store.clone(),
+            packages,
+            Arc::new(MemoryRegistry {
+                registry: registry(PluginLifecycleState::Enabled),
+            }),
+            Arc::new(FixedManifest(manifest(true))),
+        ));
+        let events = SpyEvents::default();
+        let use_case = MutateAgentPluginTool::new(
+            store,
+            Arc::new(FakeContexts),
+            resolver,
+            Arc::new(events.clone()),
+        );
+        let project = project();
+
+        use_case
+            .execute(
+                project.clone(),
+                agent_id(),
+                PluginToolRef {
+                    plugin_id: plugin_id(),
+                    server_id: PluginMcpServerId::new("unity-editor").unwrap(),
+                    tool_name: "unity_detect_project".to_owned(),
+                },
+                AssignmentMutation::Assign,
+            )
+            .await
+            .unwrap();
+
+        assert_eq!(
+            events.events(),
+            vec![DomainEvent::ProjectPluginSettingsChanged {
+                project_id: project.id,
+            }]
+        );
+    }
 }

crates/application/tests/window_usecases.rs

@@ -108,7 +108,10 @@ impl FakePluginPackages {
 #[async_trait]
 impl PluginPackageStore for FakePluginPackages {
     async fn list_installed(&self) -> Result<Vec<PluginPackageRef>, PluginStoreError> {
-        Ok(Vec::new())
+        Ok(vec![PluginPackageRef {
+            plugin_id: Some(PluginId::new("dev.idea.android-plugin").unwrap()),
+            root: "/plugin".to_owned(),
+        }])
     }
 
     async fn read_manifest(

crates/backend/src/events.rs

@@ -148,6 +148,12 @@ pub enum DomainEventDto {
         /// Project id (UUID string).
         project_id: String,
     },
+    /// Project-scoped plugin activation or assignments changed.
+    #[serde(rename_all = "camelCase")]
+    ProjectPluginSettingsChanged {
+        /// Owning project id.
+        project_id: String,
+    },
     /// A plugin was installed.
     #[serde(rename_all = "camelCase")]
     PluginInstalled {
@@ -857,6 +863,11 @@ impl From<&DomainEvent> for DomainEventDto {
             DomainEvent::ProjectCreated { project_id } => Self::ProjectCreated {
                 project_id: project_id.to_string(),
             },
+            DomainEvent::ProjectPluginSettingsChanged { project_id } => {
+                Self::ProjectPluginSettingsChanged {
+                    project_id: project_id.to_string(),
+                }
+            }
             DomainEvent::PluginInstalled { plugin_id, version } => Self::PluginInstalled {
                 plugin_id: plugin_id.to_string(),
                 version: version.as_str().to_owned(),

crates/backend/src/lib.rs

@@ -3636,16 +3636,19 @@ impl BackendCore {
         let set_project_plugin_enabled = Arc::new(SetProjectPluginEnabled::new(
             Arc::clone(&project_plugin_settings_store),
             Arc::clone(&plugin_package_store),
+            Arc::clone(&events_port),
         ));
         let mutate_agent_plugin_skill = Arc::new(MutateAgentPluginSkill::new(
             Arc::clone(&project_plugin_settings_store),
             Arc::clone(&contexts_port),
             Arc::clone(&project_plugin_resolver),
+            Arc::clone(&events_port),
         ));
         let mutate_agent_plugin_tool = Arc::new(MutateAgentPluginTool::new(
             Arc::clone(&project_plugin_settings_store),
             Arc::clone(&contexts_port),
             Arc::clone(&project_plugin_resolver),
+            Arc::clone(&events_port),
         ));
 
         // --- Memory use cases (LOT A — §14.5.1) ---

crates/domain/src/events.rs

@@ -92,6 +92,11 @@ pub enum DomainEvent {
         /// The new project.
         project_id: ProjectId,
     },
+    /// Project-scoped plugin activation or assignments changed.
+    ProjectPluginSettingsChanged {
+        /// Project whose `.ideai/project-plugins.json` was persisted.
+        project_id: ProjectId,
+    },
     /// A plugin was installed.
     PluginInstalled {
         /// Plugin id.

frontend/src/domain/index.ts

@@ -294,6 +294,7 @@ export type AgentRestartFailureCode =
 
 export type DomainEvent =
   | { type: "projectCreated"; projectId: string }
+  | { type: "projectPluginSettingsChanged"; projectId: string }
   | { type: "pluginInstalled"; pluginId: string; version: string }
   | {
       type: "pluginReloaded";
@@ -302,6 +303,10 @@ export type DomainEvent =
       newContentHash: string;
       changed: boolean;
     }
+  | { type: "pluginEnabled"; pluginId: string }
+  | { type: "pluginDisabled"; pluginId: string; restartRequired: boolean }
+  | { type: "pluginUninstalled"; pluginId: string; restartRequired: boolean }
+  | { type: "pluginLoadFailed"; pluginId: string; reason: string }
   | { type: "agentLaunched"; agentId: string; sessionId: string }
   | { type: "agentExited"; agentId: string; code: number }
   | {

frontend/src/features/agents/AgentsPanel.tsx

@@ -264,12 +264,16 @@ export function AgentsPanel({ projectId, projectRoot = "" }: AgentsPanelProps) {
   return (
     <Panel title={tr("Agents", "Agents")} className="flex flex-col gap-0">
       {vm.error && (
-        <p
+        <div
           role="alert"
-          className="mx-4 mt-3 rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-sm text-danger"
+          className="mx-4 mt-3 flex flex-wrap items-center gap-2 rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-sm text-danger"
         >
-          {vm.error}
-        </p>
+          <span>{tr("Mise à jour interrompue.", "Update interrupted.")}</span>
+          <span>{vm.error}</span>
+          <Button size="sm" variant="secondary" onClick={() => void vm.refresh()}>
+            {tr("Réessayer", "Retry")}
+          </Button>
+        </div>
       )}
 
       {/* ── Create form ── */}

frontend/src/features/layout/LayoutGrid.cellControlsLayering.test.tsx

@@ -160,10 +160,11 @@ function controlsFor(cellId: string) {
 
 type CellAction = "selector" | "split" | "close";
 
-function performAction(action: CellAction, cellId: string) {
+async function performAction(action: CellAction, cellId: string) {
   const { selector, splitColumns, close } = controlsFor(cellId);
   if (action === "selector") {
-    fireEvent.change(selector, { target: { value: "" } });
+    fireEvent.click(selector);
+    fireEvent.click(await screen.findByRole("option", { name: "Terminal" }));
   } else if (action === "split") {
     fireEvent.click(splitColumns);
   } else {
@@ -443,7 +444,8 @@ describe("LayoutGrid — ticket #48 cell control layering", () => {
     );
 
     const selector = screen.getByLabelText(`Sélecteur d’agent ${setup.bId}`);
-    fireEvent.change(selector, { target: { value: setup.otherAgentId } });
+    fireEvent.click(selector);
+    fireEvent.click(await screen.findByRole("option", { name: "Reviewer" }));
     await waitFor(() =>
       expect(mutate).toHaveBeenCalledWith(
         "p1",
@@ -509,7 +511,7 @@ describe("LayoutGrid — ticket #48 cell control layering", () => {
       expect(controls.style.zIndex).toBe("5");
       expect(error.style.zIndex).toBe("3");
 
-      performAction(action, setup.bId);
+      await performAction(action, setup.bId);
       await waitFor(() =>
         expect(mutate).toHaveBeenCalledWith(
           "p1",
@@ -538,7 +540,7 @@ describe("LayoutGrid — ticket #48 cell control layering", () => {
       expect(overlay.className).toContain("z-[4]");
       expect(overlay.className).toContain("pointer-events-none");
 
-      performAction(action, setup.bId);
+      await performAction(action, setup.bId);
       await waitFor(() =>
         expect(mutate).toHaveBeenCalledWith(
           "p1",

frontend/src/features/layout/LayoutGrid.tsx

@@ -29,6 +29,7 @@ import type {
 import { TerminalView, useWritePortal } from "@/features/terminals";
 import { useGateways } from "@/app/di";
 import { useI18n } from "@/i18n";
+import { SmallDropdown } from "@/shared";
 import { useProjectWorkState } from "@/features/workstate/useProjectWorkState";
 import {
   AgentRestartOverlay,
@@ -1359,12 +1360,11 @@ function LeafView({
         }}
       >
         {/* Agent selector */}
-        <select
+        <SmallDropdown
           aria-label={`${tr("Sélecteur d’agent", "Agent selector")} ${id}`}
           value={agentId ?? ""}
           disabled={cellRestartBusy}
-          onChange={(e) => {
-            const val = e.target.value;
+          onChange={(val) => {
             if (val === "") {
               setBusyNotice(null);
               void (async () => {
@@ -1415,29 +1415,23 @@ function LeafView({
               setBusyNotice(await noticeFromError(err, val)),
             );
           }}
-          style={{
-            fontSize: 11,
-            background: "var(--color-surface, #1e1e1e)",
-            color: "var(--color-content, #e0e0e0)",
-            border: "1px solid var(--color-border, #3a3a3a)",
-            borderRadius: 3,
-            padding: "1px 2px",
-            width: 96,
-            minWidth: 56,
-          }}
-        >
-          <option value="">{tr("Terminal", "Plain")}</option>
-          {agents.map((a) => {
-            const elsewhere = visibleElsewhere(a.id);
-            const background = backgroundLive(a.id);
-            return (
-              <option key={a.id} value={a.id} disabled={Boolean(elsewhere)}>
-                {a.name}
-                {elsewhere ? tr(" (visible ailleurs)", " (visible elsewhere)") : background ? tr(" (arrière-plan)", " (background)") : ""}
-              </option>
-            );
-          })}
-        </select>
+          className="h-6 w-24 min-w-14 rounded px-1.5 py-0 text-[11px]"
+          options={[
+            { value: "", label: tr("Terminal", "Plain") },
+            ...agents.map((a) => {
+              const elsewhere = visibleElsewhere(a.id);
+              const background = backgroundLive(a.id);
+              return {
+                value: a.id,
+                label: `${a.name}${elsewhere ? tr(" (visible ailleurs)", " (visible elsewhere)") : background ? tr(" (arrière-plan)", " (background)") : ""}`,
+                disabled: Boolean(elsewhere),
+              };
+            }),
+            ...(agents.length === 0
+              ? [{ value: "__no-agents__", label: tr("Aucun agent disponible", "No agent available"), disabled: true }]
+              : []),
+          ]}
+        />
 
         {(effectiveCustomCliAvailable || (agentId && cellMode === "custom")) && (
           <div

frontend/src/features/layout/setCellAgent.test.tsx

@@ -34,7 +34,13 @@ function renderGrid(
 }
 
 async function waitForAgentOption(name = "MyAgent") {
-  await screen.findByRole("option", { name });
+  const selector = await screen.findByRole("combobox");
+  if (selector.getAttribute("aria-expanded") !== "true") fireEvent.click(selector);
+  return screen.findByRole("option", { name });
+}
+
+async function chooseAgent(name = "MyAgent") {
+  fireEvent.click(await waitForAgentOption(name));
 }
 
 describe("setCellAgent (agent dropdown per cell)", () => {
@@ -63,10 +69,7 @@ describe("setCellAgent (agent dropdown per cell)", () => {
     await waitFor(() => {
       expect(screen.getByRole("combobox")).toBeTruthy();
     });
-    await waitForAgentOption();
-
-    const select = screen.getByRole("combobox") as HTMLSelectElement;
-    fireEvent.change(select, { target: { value: a.id } });
+    await chooseAgent();
 
     // The layout should persist the agent on the leaf.
     const initial = await layout.loadLayout("p1");
@@ -129,9 +132,9 @@ describe("setCellAgent (agent dropdown per cell)", () => {
       expect(sel).toBeTruthy();
     });
 
-    const select = screen.getByRole("combobox") as HTMLSelectElement;
     // Switch back to Plain.
-    fireEvent.change(select, { target: { value: "" } });
+    fireEvent.click(screen.getByRole("combobox"));
+    fireEvent.click(await screen.findByRole("option", { name: "Terminal" }));
 
     // After clearing, the layout should have no agent on the leaf.
     await waitFor(async () => {
@@ -157,9 +160,7 @@ describe("setCellAgent (agent dropdown per cell)", () => {
 
     renderGrid(layout, agent);
     await waitFor(() => expect(screen.getByRole("combobox")).toBeTruthy());
-    await waitForAgentOption();
-
-    fireEvent.change(screen.getByRole("combobox"), { target: { value: a.id } });
+    await chooseAgent();
 
     await waitFor(async () => {
       const fresh = await layout.loadLayout("p1");
@@ -175,7 +176,7 @@ describe("setCellAgent (agent dropdown per cell)", () => {
     const agent = new MockAgentGateway();
     const terminal = new MockTerminalGateway();
     const closeSpy = vi.spyOn(terminal, "closeTerminal");
-    const a = await agent.createAgent("p1", { name: "MyAgent", profileId: "p" });
+    await agent.createAgent("p1", { name: "MyAgent", profileId: "p" });
 
     const tree = await layout.loadLayout("p1");
     const leafId = leaves(tree)[0].id;
@@ -187,9 +188,7 @@ describe("setCellAgent (agent dropdown per cell)", () => {
 
     renderGrid(layout, agent, "p1", terminal);
     await waitFor(() => expect(screen.getByRole("combobox")).toBeTruthy());
-    await waitForAgentOption();
-
-    fireEvent.change(screen.getByRole("combobox"), { target: { value: a.id } });
+    await chooseAgent();
 
     await waitFor(() => {
       expect(closeSpy).toHaveBeenCalledWith("old-session");
@@ -205,9 +204,7 @@ describe("setCellAgent (agent dropdown per cell)", () => {
 
     renderGrid(layout, agent, "p1", terminal);
     await waitFor(() => expect(screen.getByRole("combobox")).toBeTruthy());
-    await waitForAgentOption();
-
-    fireEvent.change(screen.getByRole("combobox"), { target: { value: a.id } });
+    await chooseAgent();
 
     await waitFor(async () => {
       const fresh = await layout.loadLayout("p1");
@@ -262,9 +259,17 @@ describe("setCellAgent (agent dropdown per cell)", () => {
 
     renderGrid(layout, agent);
 
-    await waitFor(() => {
-      expect(screen.getByText("Agent Alpha")).toBeTruthy();
-      expect(screen.getByText("Agent Beta")).toBeTruthy();
-    });
+    fireEvent.click(await screen.findByRole("combobox"));
+    expect(await screen.findByRole("option", { name: "Agent Alpha" })).toBeTruthy();
+    expect(screen.getByRole("option", { name: "Agent Beta" })).toBeTruthy();
+  });
+
+  it("shows a themed empty state when the project has no agents", async () => {
+    renderGrid(new MockLayoutGateway(), new MockAgentGateway());
+
+    fireEvent.click(await screen.findByRole("combobox"));
+    const list = await screen.findByRole("listbox");
+    expect(list.className).toContain("bg-overlay");
+    expect((screen.getByRole("option", { name: "Aucun agent disponible" }) as HTMLButtonElement).disabled).toBe(true);
   });
 });

frontend/src/features/layout/singletonAgent.test.tsx

@@ -112,6 +112,11 @@ describe("singleton agent — dropdown guard (T6)", () => {
     );
   }
 
+  async function openAgentOption(name: RegExp | string) {
+    fireEvent.click(await screen.findByRole("combobox"));
+    return screen.findByRole("option", { name });
+  }
+
   it("opens an agent already running elsewhere by rebinding its live session", async () => {
     const layout = new MockLayoutGateway();
     const agent = new MockAgentGateway();
@@ -129,13 +134,9 @@ describe("singleton agent — dropdown guard (T6)", () => {
     renderGrid(layout, agent);
 
     // The option is selectable: choosing it rebinds the running session here.
-    const option = await screen.findByRole("option", {
-      name: /Busy/,
-    });
-    expect((option as HTMLOptionElement).disabled).toBe(false);
-
-    const select = screen.getByRole("combobox") as HTMLSelectElement;
-    fireEvent.change(select, { target: { value: a.id } });
+    const option = await openAgentOption(/Busy/);
+    expect((option as HTMLButtonElement).disabled).toBe(false);
+    fireEvent.click(option);
 
     await waitFor(async () => {
       const updated = await layout.loadLayout("p1");
@@ -165,13 +166,9 @@ describe("singleton agent — dropdown guard (T6)", () => {
 
     renderGrid(layout, agent);
 
-    const option = await screen.findByRole("option", {
-      name: /Busy/,
-    });
-    expect((option as HTMLOptionElement).disabled).toBe(false);
-
-    const select = screen.getByRole("combobox") as HTMLSelectElement;
-    fireEvent.change(select, { target: { value: a.id } });
+    const option = await openAgentOption(/Busy/);
+    expect((option as HTMLButtonElement).disabled).toBe(false);
+    fireEvent.click(option);
 
     expect((await screen.findByRole("status")).textContent).toMatch(
       /Session active introuvable/,
@@ -198,11 +195,9 @@ describe("singleton agent — dropdown guard (T6)", () => {
 
     renderGrid(layout, agent);
 
-    const option = await screen.findByRole("option", { name: /Headless/ });
-    expect((option as HTMLOptionElement).disabled).toBe(false);
-
-    const select = screen.getByRole("combobox") as HTMLSelectElement;
-    fireEvent.change(select, { target: { value: a.id } });
+    const option = await openAgentOption(/Headless/);
+    expect((option as HTMLButtonElement).disabled).toBe(false);
+    fireEvent.click(option);
 
     await waitFor(async () => {
       const updated = await layout.loadLayout("p1");
@@ -234,9 +229,9 @@ describe("singleton agent — dropdown guard (T6)", () => {
 
     renderGrid(layout, agent);
 
-    const option = await screen.findByRole("option", { name: "Mine" });
+    const option = await openAgentOption("Mine");
     // Live on its own cell ⇒ NOT disabled (it can keep running here).
-    expect((option as HTMLOptionElement).disabled).toBe(false);
+    expect((option as HTMLButtonElement).disabled).toBe(false);
   });
 });
 
@@ -291,23 +286,13 @@ describe("R0d — dropdown disables agents live elsewhere + go-to-cell", () => {
     renderGrid(layout, agent);
 
     // In cell A's dropdown the option is DISABLED (cannot run in two cells).
-    const selectA = (await screen.findByLabelText(
+    const selectA = await screen.findByLabelText(
       `Sélecteur d’agent ${a}`,
-    )) as HTMLSelectElement;
-    await waitFor(() => {
-      const opt = Array.from(selectA.options).find((o) => o.value === ag.id)!;
-      expect(opt.disabled).toBe(true);
-      expect(opt.textContent).toMatch(/visible ailleurs/);
-    });
-
-    // Selecting it surfaces a clear notice + an "aller à la cellule" action.
-    fireEvent.change(selectA, { target: { value: ag.id } });
-    expect((await screen.findByRole("status")).textContent).toMatch(
-      /déjà actif dans une autre cellule/,
     );
-    expect(
-      screen.getByRole("button", { name: "aller à la cellule" }),
-    ).toBeTruthy();
+    fireEvent.click(selectA);
+    const opt = await screen.findByRole("option", { name: /Busy.*visible ailleurs/ });
+    expect((opt as HTMLButtonElement).disabled).toBe(true);
+    expect(opt.textContent).toMatch(/visible ailleurs/);
   });
 
   it("an agent NOT live anywhere stays selectable (no regression)", async () => {
@@ -320,13 +305,13 @@ describe("R0d — dropdown disables agents live elsewhere + go-to-cell", () => {
 
     renderGrid(layout, agent);
 
+    fireEvent.click(await screen.findByRole("combobox"));
     const option = await screen.findByRole("option", { name: "Free" });
-    expect((option as HTMLOptionElement).disabled).toBe(false);
+    expect((option as HTMLButtonElement).disabled).toBe(false);
 
     // And selecting it pins the agent on the cell (no notice, no block).
     const leafId = leaves(await layout.loadLayout("p1"))[0].id;
-    const select = screen.getByRole("combobox") as HTMLSelectElement;
-    fireEvent.change(select, { target: { value: ag.id } });
+    fireEvent.click(option);
     await waitFor(async () => {
       const leaf = leaves(await layout.loadLayout("p1")).find(
         (l) => l.id === leafId,
@@ -396,18 +381,16 @@ describe("ticket #56 — 'visible ailleurs' derives from the layout, not stale l
     // In cell B's dropdown, X is ENABLED and flagged as a background session —
     // NOT "visible ailleurs" (regression: it used to be disabled via the stale
     // live nodeId still pointing at the now-visible cell A).
-    const selectB = (await screen.findByLabelText(
+    const selectB = await screen.findByLabelText(
       `Sélecteur d’agent ${b}`,
-    )) as HTMLSelectElement;
-    await waitFor(() => {
-      const opt = Array.from(selectB.options).find((o) => o.value === x.id)!;
-      expect(opt.disabled).toBe(false);
-      expect(opt.textContent).toMatch(/arrière-plan/);
-      expect(opt.textContent).not.toMatch(/visible ailleurs/);
-    });
+    );
+    fireEvent.click(selectB);
+    const opt = await screen.findByRole("option", { name: /Xavier.*arrière-plan/ });
+    expect((opt as HTMLButtonElement).disabled).toBe(false);
+    expect(opt.textContent).not.toMatch(/visible ailleurs/);
 
     // Selecting X in B re-attaches its live session (no re-spawn) and pins it here.
-    fireEvent.change(selectB, { target: { value: x.id } });
+    fireEvent.click(opt);
     await waitFor(async () => {
       const leaf = leaves(await layout.loadLayout("p1")).find((l) => l.id === b)!;
       expect(leaf.agent).toBe(x.id);
@@ -438,13 +421,11 @@ describe("ticket #56 — 'visible ailleurs' derives from the layout, not stale l
 
     renderGrid(layout, agent);
 
-    const selectB = (await screen.findByLabelText(
+    const selectB = await screen.findByLabelText(
       `Sélecteur d’agent ${b}`,
-    )) as HTMLSelectElement;
-    await waitFor(() => {
-      const opt = Array.from(selectB.options).find((o) => o.value === x.id)!;
-      expect(opt.disabled).toBe(true);
-      expect(opt.textContent).toMatch(/visible ailleurs/);
-    });
+    );
+    fireEvent.click(selectB);
+    const opt = await screen.findByRole("option", { name: /Xavier.*visible ailleurs/ });
+    expect((opt as HTMLButtonElement).disabled).toBe(true);
   });
 });

frontend/src/features/plugins/PluginRuntimeProvider.test.tsx

@@ -132,6 +132,17 @@ describe("PluginRuntimeProvider soft refresh (#279)", () => {
     expect(mounts).toBe(1);
     expect(plugin.calls).toBe(3);
     expect(plugin.projectIds).toEqual(["project-1", "project-1", "project-1"]);
+
+    plugin.catalog = { plugins: [] };
+    system.emit({ type: "projectPluginSettingsChanged", projectId: "another-project" });
+    await new Promise((resolve) => setTimeout(resolve, 0));
+    expect(plugin.calls).toBe(3);
+
+    system.emit({ type: "projectPluginSettingsChanged", projectId: "project-1" });
+    expect(await screen.findByText("none")).toBeTruthy();
+    expect(screen.getByTestId("workspace-state").textContent).toBe("preserved");
+    expect(mounts).toBe(1);
+    expect(plugin.calls).toBe(4);
   });
 
   it("ignores a custom plugin layout ref when its contribution disappears", async () => {

frontend/src/features/plugins/PluginRuntimeProvider.tsx

@@ -179,7 +179,16 @@ export function PluginRuntimeProvider({ children, value: injected }: PluginRunti
 
     void gateways.system
       .onDomainEvent((event) => {
-        if (event.type === "pluginInstalled" || event.type === "pluginReloaded") {
+        const globalCatalogChanged =
+          event.type === "pluginInstalled" ||
+          event.type === "pluginReloaded" ||
+          event.type === "pluginEnabled" ||
+          event.type === "pluginDisabled" ||
+          event.type === "pluginUninstalled";
+        const currentProjectChanged =
+          event.type === "projectPluginSettingsChanged" &&
+          event.projectId === currentProjectId;
+        if (globalCatalogChanged || currentProjectChanged) {
           void refreshRuntime(false);
         }
       })

frontend/src/features/plugins/ProjectPluginSettings.test.tsx

@@ -5,6 +5,7 @@ import { DIProvider } from "@/app/di";
 import {
   createMockGateways,
   MockPluginGateway,
+  MockSystemGateway,
 } from "@/adapters/mock";
 import type { ProjectPluginManifest } from "@/domain";
 import { SkillsPanel } from "@/features/skills";
@@ -91,6 +92,53 @@ describe("project plugin settings #282", () => {
     expect(onAssignAgents).toHaveBeenCalledOnce();
   });
 
+  it("refreshes project settings on the matching domain event without remounting", async () => {
+    const gateways = gatewaysWithPlugin();
+    const system = new MockSystemGateway();
+    const scoped = { ...gateways, system };
+    render(
+      <DIProvider gateways={scoped}>
+        <ProjectPluginsPanel projectId="project-1" />
+      </DIProvider>,
+    );
+
+    const toggle = await screen.findByRole("checkbox", { name: "Activé pour ce projet" });
+    expect((toggle as HTMLInputElement).checked).toBe(false);
+    gateways.plugin._seedProjectPluginSettings("project-1", {
+      version: 1,
+      plugins: [{ pluginId: "dev.acme.unity", enabled: true }],
+      agents: [],
+    });
+
+    system.emit({ type: "projectPluginSettingsChanged", projectId: "other-project" });
+    expect((toggle as HTMLInputElement).checked).toBe(false);
+    system.emit({ type: "projectPluginSettingsChanged", projectId: "project-1" });
+    await waitFor(() => expect((toggle as HTMLInputElement).checked).toBe(true));
+  });
+
+  it("keeps the previous activation after failure and retries the requested state", async () => {
+    const gateways = gatewaysWithPlugin();
+    const original = gateways.plugin.setProjectEnabled.bind(gateways.plugin);
+    const update = vi
+      .spyOn(gateways.plugin, "setProjectEnabled")
+      .mockRejectedValueOnce(new Error("settings unavailable"))
+      .mockImplementation(original);
+    render(
+      <DIProvider gateways={gateways}>
+        <ProjectPluginsPanel projectId="project-1" />
+      </DIProvider>,
+    );
+
+    const toggle = await screen.findByRole("checkbox", { name: "Activé pour ce projet" });
+    fireEvent.click(toggle);
+    expect(await screen.findByText("Erreur — état précédent conservé")).toBeTruthy();
+    expect((toggle as HTMLInputElement).checked).toBe(false);
+
+    fireEvent.click(screen.getByRole("button", { name: "Réessayer" }));
+    await waitFor(() => expect((toggle as HTMLInputElement).checked).toBe(true));
+    expect(update).toHaveBeenCalledTimes(2);
+  });
+
   it("assigns plugin skills from the unified Skills panel and keeps tombstones removable", async () => {
     const gateways = gatewaysWithPlugin();
     const agent = await gateways.agent.createAgent("project-1", {

frontend/src/features/plugins/ProjectPluginsPanel.tsx

@@ -48,7 +48,21 @@ export function ProjectPluginsPanel({
         )}
       </div>
 
-      {vm.error && <p role="alert" className="text-sm text-danger">{vm.error}</p>}
+      {vm.error && (
+        <div role="alert" className="flex flex-wrap items-center gap-2 rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-sm text-danger">
+          <span>{tr("Mise à jour interrompue.", "Update interrupted.")}</span>
+          <span>{vm.error}</span>
+          <Button
+            size="sm"
+            variant="secondary"
+            onClick={() => void (vm.failedActivation
+              ? vm.setEnabled(vm.failedActivation.pluginId, vm.failedActivation.enabled)
+              : vm.refresh())}
+          >
+            {tr("Réessayer", "Retry")}
+          </Button>
+        </div>
+      )}
 
       {vm.installed.length === 0 && missing.length === 0 ? (
         <Panel><p className="text-sm text-muted">{tr("Aucun plugin installé globalement.", "No globally installed plugins.")}</p></Panel>
@@ -60,6 +74,10 @@ export function ProjectPluginsPanel({
             ) ?? false;
             const skills = plugin.contributes.skills ?? [];
             const servers = plugin.contributes.mcpServers ?? [];
+            const pending = vm.pendingActivation?.pluginId === plugin.id
+              ? vm.pendingActivation
+              : null;
+            const failed = vm.failedActivation?.pluginId === plugin.id;
             return (
               <li key={plugin.id}>
                 <Panel className="flex flex-col gap-3">
@@ -86,6 +104,15 @@ export function ProjectPluginsPanel({
                       {tr("Activé pour ce projet", "Enabled for this project")}
                     </label>
                   </div>
+                  {(pending || failed) && (
+                    <p role={failed ? "alert" : "status"} className={`text-xs ${failed ? "text-danger" : "text-muted"}`}>
+                      {failed
+                        ? tr("Erreur — état précédent conservé", "Error — previous state preserved")
+                        : pending?.enabled
+                          ? tr("Activation…", "Enabling…")
+                          : tr("Désactivation…", "Disabling…")}
+                    </p>
+                  )}
 
                   <details>
                     <summary className="cursor-pointer text-xs font-medium text-primary">

frontend/src/features/plugins/usePluginMenus.test.tsx

@@ -1,4 +1,4 @@
-import { renderHook } from "@testing-library/react";
+import { act, renderHook } from "@testing-library/react";
 import { describe, expect, it, vi } from "vitest";
 
 import type { MenuTargetId } from "@/domain";
@@ -16,6 +16,8 @@ const NO_CONTEXT: WhenContext = {
 function throwingRegistry(overrides: Record<string, unknown>): PluginRuntimeRegistry {
   return {
     runCommand: vi.fn(async () => {}),
+    runCommandStrict: vi.fn(async () => {}),
+    get: vi.fn(() => ({ commands: { has: () => true } })),
     topLevelMenus: vi.fn(() => []),
     menuItems: vi.fn(() => []),
     ...overrides,
@@ -72,4 +74,50 @@ describe("usePluginMenus", () => {
       consoleWarn.mockRestore();
     }
   });
+
+  it("logs rejected commands and exposes retryable feedback to the host", async () => {
+    const failure = new Error("native window refused");
+    const runCommandStrict = vi.fn().mockRejectedValueOnce(failure).mockResolvedValueOnce("opened");
+    const consoleError = vi.spyOn(console, "error").mockImplementation(() => {});
+    try {
+      const registry = throwingRegistry({ runCommandStrict });
+      const { result } = renderHook(() => usePluginMenus(registry, NO_CONTEXT));
+
+      await act(() => result.current.runCommand("dev.acme.git", "git.configure"));
+
+      expect(consoleError).toHaveBeenCalledWith(
+        "[plugins] menu command rejected",
+        {
+          pluginId: "dev.acme.git",
+          commandId: "git.configure",
+          message: "native window refused",
+        },
+      );
+      expect(result.current.commandError).toEqual({
+        pluginId: "dev.acme.git",
+        commandId: "git.configure",
+        message: "native window refused",
+      });
+
+      await act(() => result.current.runCommand("dev.acme.git", "git.configure"));
+      expect(result.current.commandError).toBeNull();
+      expect(runCommandStrict).toHaveBeenCalledTimes(2);
+    } finally {
+      consoleError.mockRestore();
+    }
+  });
+
+  it("keeps a missing command handler as a silent no-op", async () => {
+    const runCommandStrict = vi.fn();
+    const registry = throwingRegistry({
+      runCommandStrict,
+      get: vi.fn(() => ({ commands: { has: () => false } })),
+    });
+    const { result } = renderHook(() => usePluginMenus(registry, NO_CONTEXT));
+
+    await act(() => result.current.runCommand("dev.acme.git", "git.missing"));
+
+    expect(runCommandStrict).not.toHaveBeenCalled();
+    expect(result.current.commandError).toBeNull();
+  });
 });

frontend/src/features/plugins/usePluginMenus.ts

@@ -11,7 +11,7 @@
  * future lot threads real focus state up to this level).
  */
 
-import { useMemo } from "react";
+import { useCallback, useMemo, useState } from "react";
 
 import type { MenuTargetId } from "@/domain";
 import type { MenuBarItem, MenuBarMenu } from "@/shared";
@@ -24,6 +24,14 @@ export interface UsePluginMenusResult {
   /** Resolved+ordered `MenuBarItem`s to append to a native menu's items. */
   itemsFor: (targetMenuId: MenuTargetId) => MenuBarItem[];
   runCommand: (pluginId: string, commandId: string) => Promise<unknown>;
+  commandError: PluginMenuCommandError | null;
+  clearCommandError: () => void;
+}
+
+export interface PluginMenuCommandError {
+  pluginId: string;
+  commandId: string;
+  message: string;
 }
 
 function describeError(e: unknown): string {
@@ -49,8 +57,25 @@ export function usePluginMenus(
   registry: PluginRuntimeRegistry,
   whenCtx: WhenContext,
 ): UsePluginMenusResult {
-  const runCommand = useMemo(
-    () => (pluginId: string, commandId: string) => registry.runCommand(pluginId, commandId),
+  const [commandError, setCommandError] = useState<PluginMenuCommandError | null>(null);
+  const clearCommandError = useCallback(() => setCommandError(null), []);
+  const runCommand = useCallback(
+    async (pluginId: string, commandId: string): Promise<unknown> => {
+      setCommandError(null);
+      try {
+        // Preserve the SDK's historical no-op for a declared menu command whose
+        // handler was not registered, but do not use the lenient dispatcher for
+        // real handlers: it logs and swallows rejected promises, which made
+        // native-window failures invisible to the menu host (#329).
+        if (!registry.get(pluginId)?.commands.has(commandId)) return undefined;
+        return await registry.runCommandStrict(pluginId, commandId);
+      } catch (error) {
+        const failure = { pluginId, commandId, message: describeError(error) };
+        console.error("[plugins] menu command rejected", failure);
+        setCommandError(failure);
+        return undefined;
+      }
+    },
     [registry],
   );
 
@@ -126,5 +151,5 @@ export function usePluginMenus(
     });
   }, [registry, itemsFor]);
 
-  return { topLevelMenus, itemsFor, runCommand };
+  return { topLevelMenus, itemsFor, runCommand, commandError, clearCommandError };
 }

frontend/src/features/plugins/useProjectPlugins.ts

@@ -1,4 +1,4 @@
-import { useCallback, useEffect, useState } from "react";
+import { useCallback, useEffect, useRef, useState } from "react";
 
 import { useGateways } from "@/app/di";
 import type {
@@ -21,6 +21,8 @@ export interface ProjectPluginsViewModel {
   loading: boolean;
   busy: boolean;
   error: string | null;
+  pendingActivation: { pluginId: string; enabled: boolean } | null;
+  failedActivation: { pluginId: string; enabled: boolean } | null;
   refresh(): Promise<void>;
   setEnabled(pluginId: string, enabled: boolean): Promise<void>;
   setSkillAssigned(agentId: string, pluginId: string, skillId: string, assigned: boolean): Promise<void>;
@@ -28,31 +30,91 @@ export interface ProjectPluginsViewModel {
 }
 
 export function useProjectPlugins(projectId: string): ProjectPluginsViewModel {
-  const { plugin } = useGateways();
+  const { plugin, system } = useGateways();
   const [installed, setInstalled] = useState<ProjectPluginManifest[]>([]);
   const [settings, setSettings] = useState<ProjectPluginSettings | null>(null);
   const [loading, setLoading] = useState(true);
   const [busy, setBusy] = useState(false);
   const [error, setError] = useState<string | null>(null);
+  const [pendingActivation, setPendingActivation] = useState<{
+    pluginId: string;
+    enabled: boolean;
+  } | null>(null);
+  const [failedActivation, setFailedActivation] = useState<{
+    pluginId: string;
+    enabled: boolean;
+  } | null>(null);
+  const refreshRevision = useRef(0);
+  const currentProjectId = useRef(projectId);
+  currentProjectId.current = projectId;
 
   const refresh = useCallback(async () => {
+    const revision = ++refreshRevision.current;
+    const refreshedProjectId = projectId;
     setLoading(true);
     setError(null);
     try {
-      const view = await plugin.listProjectSettings(projectId);
+      const view = await plugin.listProjectSettings(refreshedProjectId);
+      if (
+        revision !== refreshRevision.current ||
+        currentProjectId.current !== refreshedProjectId
+      ) return;
       setInstalled(view.installed);
       setSettings(view.settings);
     } catch (cause) {
+      if (
+        revision !== refreshRevision.current ||
+        currentProjectId.current !== refreshedProjectId
+      ) return;
       setError(describe(cause));
     } finally {
-      setLoading(false);
+      if (
+        revision === refreshRevision.current &&
+        currentProjectId.current === refreshedProjectId
+      ) setLoading(false);
     }
   }, [plugin, projectId]);
 
   useEffect(() => {
+    setInstalled([]);
+    setSettings(null);
+    setBusy(false);
+    setError(null);
+    setPendingActivation(null);
+    setFailedActivation(null);
     void refresh();
+    return () => {
+      refreshRevision.current += 1;
+    };
   }, [refresh]);
 
+  useEffect(() => {
+    if (!system?.onDomainEvent) return;
+    let unsubscribe: (() => void) | undefined;
+    let cancelled = false;
+    void system
+      .onDomainEvent((event) => {
+        const globalCatalogChanged =
+          event.type === "pluginInstalled" ||
+          event.type === "pluginReloaded" ||
+          event.type === "pluginEnabled" ||
+          event.type === "pluginDisabled" ||
+          event.type === "pluginUninstalled";
+        const currentProjectChanged =
+          event.type === "projectPluginSettingsChanged" &&
+          event.projectId === currentProjectId.current;
+        if (globalCatalogChanged || currentProjectChanged) void refresh();
+      })
+      .then((next) => {
+        if (cancelled) next();
+        else unsubscribe = next;
+      });
+    return () => {
+      cancelled = true;
+      unsubscribe?.();
+    };
+  }, [refresh, system]);
+
   const mutate = useCallback(async (operation: () => Promise<ProjectPluginSettings>) => {
     setBusy(true);
     setError(null);
@@ -65,11 +127,30 @@ export function useProjectPlugins(projectId: string): ProjectPluginsViewModel {
     }
   }, []);
 
-  const setEnabled = useCallback(
-    (pluginId: string, enabled: boolean) =>
-      mutate(() => plugin.setProjectEnabled({ projectId, pluginId, enabled })),
-    [mutate, plugin, projectId],
-  );
+  const setEnabled = useCallback(async (pluginId: string, enabled: boolean) => {
+    const mutatedProjectId = projectId;
+    setBusy(true);
+    setError(null);
+    setFailedActivation(null);
+    setPendingActivation({ pluginId, enabled });
+    try {
+      const next = await plugin.setProjectEnabled({
+        projectId: mutatedProjectId,
+        pluginId,
+        enabled,
+      });
+      if (currentProjectId.current === mutatedProjectId) setSettings(next);
+    } catch (cause) {
+      if (currentProjectId.current !== mutatedProjectId) return;
+      setError(describe(cause));
+      setFailedActivation({ pluginId, enabled });
+    } finally {
+      if (currentProjectId.current === mutatedProjectId) {
+        setPendingActivation(null);
+        setBusy(false);
+      }
+    }
+  }, [plugin, projectId]);
 
   const setSkillAssigned = useCallback(
     (agentId: string, pluginId: string, skillId: string, assigned: boolean) => {
@@ -97,6 +178,8 @@ export function useProjectPlugins(projectId: string): ProjectPluginsViewModel {
     loading,
     busy,
     error,
+    pendingActivation,
+    failedActivation,
     refresh,
     setEnabled,
     setSkillAssigned,

frontend/src/features/projects/ProjectSettingsPanel.test.tsx

@@ -19,6 +19,23 @@ function deferred<T>() {
 }
 
 describe("ProjectSettingsPanel", () => {
+  it("composes project plugin activation between appearance and context", async () => {
+    const gateways = createMockGateways();
+    const project = await gateways.project.createProject("Alpha", "/alpha");
+
+    render(
+      <DIProvider gateways={gateways}>
+        <ProjectSettingsPanel projectId={project.id} />
+      </DIProvider>,
+    );
+
+    const appearance = await screen.findByText("Apparence");
+    const plugins = screen.getByRole("region", { name: "Plugins du projet" });
+    const context = screen.getByRole("heading", { name: "Contexte du projet", level: 2 });
+    expect(appearance.compareDocumentPosition(plugins) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+    expect(plugins.compareDocumentPosition(context) & Node.DOCUMENT_POSITION_FOLLOWING).toBeTruthy();
+  });
+
   it("persists a project colour, emits the scoped refresh, and resets to fallback", async () => {
     const gateways = createMockGateways();
     const project = await gateways.project.createProject("Alpha", "/alpha");

frontend/src/features/projects/ProjectSettingsPanel.tsx

@@ -7,6 +7,7 @@ import { Button, Panel, Spinner } from "@/shared";
 import { ProjectContextPanel } from "./ProjectContextPanel";
 import { ProjectIconPicker } from "./ProjectIconPicker";
 import { ProjectIcon, publishProjectIconChanged } from "./projectIcons";
+import { ProjectPluginsPanel } from "@/features/plugins";
 import {
   DEFAULT_PROJECT_COLOR,
   onProjectThemeChanged,
@@ -216,6 +217,8 @@ export function ProjectSettingsPanel({ projectId }: { projectId: string }) {
         )}
       </Panel>
 
+      <ProjectPluginsPanel projectId={projectId} />
+
       <section aria-labelledby="project-context-settings-title">
         <h2
           id="project-context-settings-title"

frontend/src/features/projects/ProjectsView.tsx

@@ -1033,6 +1033,36 @@ export function ProjectsView() {
           </Button>
         </div>
       )}
+      {pluginMenus.commandError && (
+        <div
+          role="alert"
+          className="mx-4 mt-2 flex shrink-0 items-center justify-between gap-3 rounded-md border border-danger/40 bg-danger/10 px-3 py-2 text-sm text-danger"
+        >
+          <span>
+            {tr("L’action du plugin a échoué.", "The plugin action failed.")} {pluginMenus.commandError.message}
+          </span>
+          <div className="flex shrink-0 gap-2">
+            <Button
+              size="sm"
+              variant="secondary"
+              onClick={() => void pluginMenus.runCommand(
+                pluginMenus.commandError!.pluginId,
+                pluginMenus.commandError!.commandId,
+              )}
+            >
+              {tr("Réessayer", "Retry")}
+            </Button>
+            <Button
+              size="sm"
+              variant="ghost"
+              aria-label={tr("Fermer l’erreur du plugin", "Dismiss plugin error")}
+              onClick={pluginMenus.clearCommandError}
+            >
+              ×
+            </Button>
+          </div>
+        </div>
+      )}
 
       {/* ── Project tab bar (#26): tabs = open projects, "+" opens Projects ── */}
       <ProjectTabs

frontend/src/features/tickets/useProjectAgents.ts

@@ -23,15 +23,14 @@ export interface ProjectAgents {
 }
 
 export function useProjectAgents(projectId: string): ProjectAgents {
-  const { agent } = useGateways();
+  const { agent, system } = useGateways();
   const [agents, setAgents] = useState<Agent[]>([]);
   const [loaded, setLoaded] = useState(false);
 
   useEffect(() => {
     let cancelled = false;
     setLoaded(false);
-    void agent
-      .listAgents(projectId)
+    const refresh = () => agent.listAgents(projectId)
       .then((list) => {
         if (!cancelled) {
           setAgents(list);
@@ -40,14 +39,31 @@ export function useProjectAgents(projectId: string): ProjectAgents {
       })
       .catch(() => {
         if (!cancelled) {
-          setAgents([]);
           setLoaded(true);
         }
       });
+    void refresh();
+
+    let unsubscribe: (() => void) | undefined;
+    if (system?.onDomainEvent) {
+      void system
+        .onDomainEvent((event) => {
+          if (
+            event.type === "agentLaunched" ||
+            event.type === "agentExited" ||
+            event.type === "agentProfileChanged"
+          ) void refresh();
+        })
+        .then((next) => {
+          if (cancelled) next();
+          else unsubscribe = next;
+        });
+    }
     return () => {
       cancelled = true;
+      unsubscribe?.();
     };
-  }, [projectId, agent]);
+  }, [projectId, agent, system]);
 
   const byId = useMemo(
     () => new Map(agents.map((a) => [a.id, a.name])),

frontend/src/shared/ui/SmallDropdown.tsx

@@ -213,6 +213,7 @@ export function SmallDropdown({
         ref={triggerRef}
         id={id}
         type="button"
+        role="combobox"
         aria-label={ariaLabel}
         aria-haspopup="listbox"
         aria-expanded={open}
@@ -256,7 +257,7 @@ export function SmallDropdown({
             role="listbox"
             aria-label={ariaLabel}
             data-placement={position.placement}
-            className="fixed overflow-y-auto rounded-md border border-border bg-surface py-1 shadow-xl"
+            className="fixed overflow-y-auto rounded-md border border-border-strong bg-overlay py-1 shadow-xl"
             style={{
               top: position.top,
               left: position.left,
@@ -281,8 +282,9 @@ export function SmallDropdown({
                   "flex min-h-8 w-full items-center px-2 text-left text-content",
                   "hover:bg-raised focus:bg-raised focus:outline-none",
                   size === "md" ? "text-sm" : "text-xs",
-                  (option.value === value || index === activeIndex) && "bg-raised",
-                  option.disabled && "cursor-not-allowed opacity-50",
+                  option.value === value && "bg-primary/15 text-content",
+                  index === activeIndex && option.value !== value && "bg-raised",
+                  option.disabled && "cursor-not-allowed text-faint opacity-60",
                 )}
               >
                 <span className="min-w-0 truncate">{option.label}</span>