feat(agents): role orchestrateur du contexte global expose et configurable par agent — isOrchestrator distinct des permissions MCP, DTO update_project_orchestrator (terminologie wire legacy conservee), refus idea_context_update explicite avec writer effectif + orientation idea_context_propose, surface AgentsPanel + adaptateurs frontend — #276 (QA verte: cargo fmt/check, tests cibles application/app-tauri/infrastructure/backend, npm typecheck, 69/69 tests frontend agents/adapters)

crates/backend/src/dto.rs

@@ -3132,6 +3132,27 @@ pub struct UpdateAgentContactableRequestDto {
     pub contactable: bool,
 }
 
+/// Request DTO for `update_project_orchestrator`.
+///
+/// The legacy `orchestrator` terminology is intentionally kept on the wire for
+/// compatibility; the product-facing role is the global project-context writer.
+#[derive(Debug, Clone, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct UpdateProjectOrchestratorRequestDto {
+    /// Id of the owning project.
+    pub project_id: String,
+    /// Existing project agent that becomes the single effective writer.
+    pub agent_id: String,
+}
+
+/// Response DTO for `update_project_orchestrator`.
+#[derive(Debug, Clone, Serialize)]
+#[serde(rename_all = "camelCase")]
+pub struct UpdateProjectOrchestratorResponseDto {
+    /// Effective writer agent id after the update.
+    pub orchestrator_agent_id: String,
+}
+
 /// Response DTO for `change_agent_profile`: the mutated agent plus the freshly
 /// relaunched session when a live session was hot-swapped (absent otherwise).
 #[derive(Debug, Clone, Serialize)]

crates/backend/src/lib.rs

@@ -57,9 +57,9 @@ use application::{
     UninstallPlugin, UnlinkIssues, UpdateAgentContactable, UpdateAgentContext, UpdateAgentEffort,
     UpdateAgentMcpToolPermissions, UpdateAgentPermissions, UpdateAgentSystemPermissions,
     UpdateIssue, UpdateIssueCarnet, UpdateLiveState, UpdateMemory, UpdateProjectContext,
-    UpdateProjectMcpToolPermissions, UpdateProjectPermissions, UpdateProjectSystemPermissions,
-    UpdateSkill, UpdateTemplate, WakeSessionProvider, WriteMemory, WriteToTerminal,
-    AGENT_MEMORY_RECALL_BUDGET,
+    UpdateProjectMcpToolPermissions, UpdateProjectOrchestrator, UpdateProjectPermissions,
+    UpdateProjectSystemPermissions, UpdateSkill, UpdateTemplate, WakeSessionProvider, WriteMemory,
+    WriteToTerminal, AGENT_MEMORY_RECALL_BUDGET,
 };
 use async_trait::async_trait;
 use domain::ports::{
@@ -1338,6 +1338,8 @@ pub struct BackendCore {
     pub update_agent_effort: Arc<UpdateAgentEffort>,
     /// Update one agent's cross-project contactability.
     pub update_agent_contactable: Arc<UpdateAgentContactable>,
+    /// Change the single agent allowed to write the global project context.
+    pub update_project_orchestrator: Arc<UpdateProjectOrchestrator>,
     /// Resolve effective permissions for one agent.
     pub resolve_agent_permissions: Arc<ResolveAgentPermissions>,
     /// Read the project system permission document.
@@ -2509,6 +2511,10 @@ impl BackendCore {
         let update_agent_effort = Arc::new(UpdateAgentEffort::new(Arc::clone(&contexts_port)));
         let update_agent_contactable =
             Arc::new(UpdateAgentContactable::new(Arc::clone(&contexts_port)));
+        let update_project_orchestrator = Arc::new(UpdateProjectOrchestrator::new(
+            Arc::clone(&contexts_port),
+            Arc::clone(&events_port),
+        ));
         let resolve_agent_permissions = Arc::new(ResolveAgentPermissions::new(Arc::clone(
             &permission_store_port,
         )));
@@ -3363,6 +3369,7 @@ impl BackendCore {
             update_agent_permissions,
             update_agent_effort,
             update_agent_contactable,
+            update_project_orchestrator,
             resolve_agent_permissions,
             get_project_system_permissions,
             update_project_system_permissions,