fix(chat): le bouton Stop de la CLI custom arrête l'agent en cascade (#187)

Le Stop du CustomAgentChatView n'annulait que le tour courant sans libérer la
session ni toucher aux tâches enfants ou appels MCP en cours. Il appelle
désormais stop_live_agent sur l'agent vivant, qui:

- ajoute le port StopAgentExecutionCascade (best-effort, idempotent), implémenté
  par OrchestratorService pour annuler les idea_run_in_background rattachés au
  rendez-vous actif (via BackgroundTaskRunner.cancel);
- cascade l'arrêt aux wait-dépendances (stop_turn_watch + preempt) pour
  interrompre les appels MCP et les attentes inter-agents;
- libère et supprime la session structurée.

UI: nouvel état "Arrêt en cours..." (bouton disabled + loading) pendant l'arrêt,
libération du sessionId, label expliquant la cascade demandée. La Tauri command
cancel_agent_chat est alignée sur stop_live_agent + stop_turn_watch agent et
dépendances.

Tests: SpyBackgroundRunner (cascade n'annule que les tâches rattachées),
workstate_actions cascade best-effort, CustomAgentChatView stop+cascade feedback
et fallback NOT_FOUND.

crates/application/src/lib.rs

@@ -249,7 +249,7 @@ pub use workstate::{
     ConversationTurnWorkPreview, ConversationWorkSummary, GetAppExitWorkGuardState,
     GetAppExitWorkGuardStateInput, GetLiveStateLean, GetProjectWorkState, GetProjectWorkStateInput,
     LeanLiveEntry, LeanLiveState, LiveWorkSession, ProjectWorkState, ReconcileLiveState,
-    ReconcileLiveStateInput, StopLiveAgent, StopLiveAgentInput, StopLiveAgentOutput,
-    TicketWorkSource, TicketWorkStatus, UpdateLiveState, UpdateLiveStateInput,
+    ReconcileLiveStateInput, StopAgentExecutionCascade, StopLiveAgent, StopLiveAgentInput,
+    StopLiveAgentOutput, TicketWorkSource, TicketWorkStatus, UpdateLiveState, UpdateLiveStateInput,
     LIVE_STATE_MAX_ENTRIES, LIVE_STATE_TTL_MS,
 };

crates/application/src/orchestrator/service.rs

@@ -24,7 +24,9 @@ use domain::conversation::{ConversationParty, ConversationRegistry, SessionRef,
 use domain::conversation_log::{ConversationTurn, TurnId, TurnRole};
 use domain::input::{InputMediator, InputSource, SubmitConfig};
 use domain::mailbox::{Ticket, TicketId};
-use domain::ports::{BackgroundTaskStore, Clock, EventBus, ProfileStore, PtyHandle};
+use domain::ports::{
+    BackgroundTaskRunner, BackgroundTaskStore, Clock, EventBus, ProfileStore, PtyHandle,
+};
 use domain::project::ProjectPath;
 use domain::{
     AgentId, AgentProfile, BackgroundTask, BackgroundTaskKind, BackgroundTaskRendezvousLink,
@@ -52,7 +54,9 @@ use crate::orchestrator::{
 };
 use crate::skill::{CreateSkill, CreateSkillInput, ReadSkill, ReadSkillInput};
 use crate::terminal::{CloseTerminal, CloseTerminalInput, StructuredSessions, TerminalSessions};
-use crate::workstate::{GetLiveStateLean, UpdateLiveState, UpdateLiveStateInput};
+use crate::workstate::{
+    GetLiveStateLean, StopAgentExecutionCascade, UpdateLiveState, UpdateLiveStateInput,
+};
 
 /// Default terminal geometry for an orchestrator-launched agent cell. The UI
 /// resizes the PTY to the real cell size on attach; these are sane starting rows
@@ -523,6 +527,9 @@ pub struct OrchestratorService {
     /// `idea_ask_agent` comme [`BackgroundTaskKind::HeadlessRendezvous`]. `None` ⇒
     /// comportement historique sans persistance de tâche (call sites non câblés).
     background_tasks: Option<Arc<dyn BackgroundTaskStore>>,
+    /// Runner runtime des tâches command-backed, utilisé ici uniquement pour la cascade
+    /// d'arrêt best-effort des `idea_run_in_background` attachés au rendez-vous actif.
+    background_runner: Option<Arc<dyn BackgroundTaskRunner>>,
     /// Service applicatif des limites de session, injecté depuis la composition root.
     /// `None` conserve les call sites/tests legacy ; les chemins conscients des limites
     /// publient alors seulement leur erreur de tour historique.
@@ -610,6 +617,7 @@ impl OrchestratorService {
             ask_liveness_probe: None,
             ask_ceiling: ASK_AGENT_CEILING,
             background_tasks: None,
+            background_runner: None,
             session_limits: None,
             spawn_background_command: None,
         }
@@ -646,6 +654,13 @@ impl OrchestratorService {
         self
     }
 
+    /// Branche le runner command-backed pour annuler les tâches enfants lors d'un stop.
+    #[must_use]
+    pub fn with_background_task_runner(mut self, runner: Arc<dyn BackgroundTaskRunner>) -> Self {
+        self.background_runner = Some(runner);
+        self
+    }
+
     /// Branche la **sonde de vivacité** (signe de vie) du rendez-vous délégué : la borne
     /// de tour devient une **fenêtre d'inactivité** réarmée à chaque progrès observé,
     /// sous le plafond [`Self::with_ask_ceiling`]. Builder additif (signature de
@@ -3101,6 +3116,40 @@ impl<'a> WaitEdgeGuard<'a> {
     }
 }
 
+#[async_trait::async_trait]
+impl StopAgentExecutionCascade for OrchestratorService {
+    async fn stop_agent_execution_children(&self, project: &Project, agent_id: AgentId) {
+        let Some(runner) = &self.background_runner else {
+            return;
+        };
+        let agent = runtime_key(project, agent_id);
+        stop_active_rendezvous_background_tasks(&self.active_rendezvous, agent, runner.as_ref())
+            .await;
+    }
+}
+
+fn active_rendezvous_background_tasks(
+    active: &StdMutex<HashMap<RuntimeAgentKey, ActiveRendezvous>>,
+    agent: RuntimeAgentKey,
+) -> Vec<TaskId> {
+    active
+        .lock()
+        .unwrap_or_else(std::sync::PoisonError::into_inner)
+        .get(&agent)
+        .map(|active| active.background_tasks.clone())
+        .unwrap_or_default()
+}
+
+async fn stop_active_rendezvous_background_tasks(
+    active: &StdMutex<HashMap<RuntimeAgentKey, ActiveRendezvous>>,
+    agent: RuntimeAgentKey,
+    runner: &dyn BackgroundTaskRunner,
+) {
+    for task_id in active_rendezvous_background_tasks(active, agent) {
+        let _ = runner.cancel(task_id).await;
+    }
+}
+
 impl Drop for WaitEdgeGuard<'_> {
     fn drop(&mut self) {
         let mut g = self
@@ -3375,6 +3424,77 @@ mod tests {
         RuntimeAgentKey::new(domain::ProjectId::from_uuid(uuid::Uuid::nil()), aid(n))
     }
 
+    #[derive(Default)]
+    struct SpyBackgroundRunner {
+        cancelled: TestMutex<Vec<TaskId>>,
+    }
+
+    #[async_trait::async_trait]
+    impl BackgroundTaskRunner for SpyBackgroundRunner {
+        async fn spawn(
+            &self,
+            spec: domain::ports::BackgroundTaskSpec,
+        ) -> Result<domain::ports::BackgroundTaskHandle, domain::ports::BackgroundTaskPortError>
+        {
+            Ok(domain::ports::BackgroundTaskHandle {
+                task_id: spec.task_id,
+            })
+        }
+
+        async fn cancel(
+            &self,
+            task_id: TaskId,
+        ) -> Result<(), domain::ports::BackgroundTaskPortError> {
+            self.cancelled.lock().unwrap().push(task_id);
+            Ok(())
+        }
+
+        fn subscribe_completions(&self) -> domain::ports::BackgroundCompletionStream {
+            Box::new(std::iter::empty())
+        }
+    }
+
+    #[tokio::test]
+    async fn stop_active_rendezvous_background_tasks_cancels_attached_tasks_only() {
+        let active = StdMutex::new(HashMap::new());
+        let target = rkey(2);
+        let unrelated = rkey(9);
+        let first = TaskId::from_uuid(uuid::Uuid::from_u128(101));
+        let second = TaskId::from_uuid(uuid::Uuid::from_u128(102));
+        let other = TaskId::from_uuid(uuid::Uuid::from_u128(999));
+        active.lock().unwrap().insert(
+            target,
+            ActiveRendezvous {
+                link: BackgroundTaskRendezvousLink {
+                    rendezvous_id: RendezvousId::from_uuid(uuid::Uuid::from_u128(201)),
+                    ticket_id: tid(202),
+                    requester_agent_id: Some(aid(1)),
+                    target_agent_id: target.agent_id,
+                    conversation_id: domain::ConversationId::from_uuid(uuid::Uuid::from_u128(203)),
+                },
+                background_tasks: vec![first, second],
+            },
+        );
+        active.lock().unwrap().insert(
+            unrelated,
+            ActiveRendezvous {
+                link: BackgroundTaskRendezvousLink {
+                    rendezvous_id: RendezvousId::from_uuid(uuid::Uuid::from_u128(301)),
+                    ticket_id: tid(302),
+                    requester_agent_id: Some(aid(1)),
+                    target_agent_id: unrelated.agent_id,
+                    conversation_id: domain::ConversationId::from_uuid(uuid::Uuid::from_u128(303)),
+                },
+                background_tasks: vec![other],
+            },
+        );
+        let runner = SpyBackgroundRunner::default();
+
+        stop_active_rendezvous_background_tasks(&active, target, &runner).await;
+
+        assert_eq!(*runner.cancelled.lock().unwrap(), vec![first, second]);
+    }
+
     /// Drop d'un garde **armé** ⇒ `cancel_head` + `mark_idle` sur la cible (c'est le
     /// comportement qui débloque un agent resté `Busy` sur un futur abandonné).
     #[test]

crates/application/src/workstate/actions.rs

@@ -9,6 +9,7 @@
 
 use std::sync::Arc;
 
+use async_trait::async_trait;
 use domain::input::InputMediator;
 use domain::{AgentId, NodeId, Project, RuntimeAgentKey, SessionId};
 
@@ -116,6 +117,18 @@ pub struct StopLiveAgentOutput {
     pub kind: LiveSessionKind,
 }
 
+/// Best-effort stopper for execution resources owned by one live agent turn.
+///
+/// Implementations must be idempotent: a missing, already-finished or already-stopped
+/// child resource is a successful no-op. Failures are deliberately not propagated by
+/// [`StopLiveAgent`], because the product contract is "stop the agent; cascade related
+/// work best-effort".
+#[async_trait]
+pub trait StopAgentExecutionCascade: Send + Sync {
+    /// Requests cancellation of child execution resources for `agent_id` in `project`.
+    async fn stop_agent_execution_children(&self, project: &Project, agent_id: AgentId);
+}
+
 /// Stops an already-running agent's live session, polymorphically.
 ///
 /// Resolves the session by agent (PTY first, then structured). A PTY session is
@@ -129,6 +142,7 @@ pub struct StopLiveAgent {
     close: Arc<CloseTerminal>,
     input: Option<Arc<dyn InputMediator>>,
     waits: Option<Arc<OrchestratorService>>,
+    cascade: Option<Arc<dyn StopAgentExecutionCascade>>,
 }
 
 impl StopLiveAgent {
@@ -140,6 +154,7 @@ impl StopLiveAgent {
             close,
             input: None,
             waits: None,
+            cascade: None,
         }
     }
 
@@ -159,6 +174,13 @@ impl StopLiveAgent {
         self
     }
 
+    /// Wires best-effort cancellation of child resources spawned by the running turn.
+    #[must_use]
+    pub fn with_execution_cascade(mut self, cascade: Arc<dyn StopAgentExecutionCascade>) -> Self {
+        self.cascade = Some(cascade);
+        self
+    }
+
     /// Tears down the agent's live session.
     ///
     /// # Errors
@@ -177,10 +199,18 @@ impl StopLiveAgent {
     }
 
     async fn stop_dependencies(&self, project: &Project, agent_id: AgentId) {
+        if let Some(cascade) = &self.cascade {
+            cascade
+                .stop_agent_execution_children(project, agent_id)
+                .await;
+        }
         let Some(waits) = &self.waits else {
             return;
         };
         for dep in waits.active_wait_dependencies(agent_id) {
+            if let Some(cascade) = &self.cascade {
+                cascade.stop_agent_execution_children(project, dep).await;
+            }
             if let Some(mediator) = &self.input {
                 mediator.preempt(RuntimeAgentKey::new(project.id, dep));
             }

crates/application/src/workstate/mod.rs

@@ -10,8 +10,8 @@ mod live;
 mod reconcile;
 
 pub use actions::{
-    AttachLiveAgent, AttachLiveAgentInput, AttachLiveAgentOutput, StopLiveAgent,
-    StopLiveAgentInput, StopLiveAgentOutput,
+    AttachLiveAgent, AttachLiveAgentInput, AttachLiveAgentOutput, StopAgentExecutionCascade,
+    StopLiveAgent, StopLiveAgentInput, StopLiveAgentOutput,
 };
 pub use live::{
     GetLiveStateLean, LeanLiveEntry, LeanLiveState, UpdateLiveState, UpdateLiveStateInput,