feat: livrable ticket #91 — notification fin BackgroundTask enrichie

- Backend: enrichissement HeadlessRendezvous avec requester/target/conversationId
- Frontend: toast 'Requester -> Target completed/...' explicite
- Clic ouvrant viewer de conversation pour visualiser l'échange

crates/domain/src/events.rs

@@ -1,7 +1,7 @@
 //! Domain events published on the [`crate::ports::EventBus`] and relayed to the
 //! presentation layer (ARCHITECTURE §3.2).
 
-use crate::conversation::ConversationParty;
+use crate::conversation::{ConversationId, ConversationParty};
 use crate::device::DeviceId;
 use crate::ids::{
     AgentId, IssueId, LocalModelServerId, ProfileId, ProjectId, SessionId, SkillId, SprintId,
@@ -14,6 +14,18 @@ use crate::plugin::{PluginId, PluginMcpServerId, PluginVersion};
 use crate::sprint::{SprintOrder, SprintVersion};
 use crate::template::TemplateVersion;
 
+/// Context carried by terminal background-task events when they come from a
+/// headless inter-agent rendezvous.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct RendezvousContext {
+    /// Agent that requested the rendezvous, when known.
+    pub requester_agent_id: Option<AgentId>,
+    /// Target agent that owns the rendezvous conversation.
+    pub target_agent_id: AgentId,
+    /// Conversation opened by the target turn.
+    pub conversation_id: ConversationId,
+}
+
 /// Which entry door a processed orchestration request arrived through.
 ///
 /// IdeA exposes the *same* [`crate::OrchestratorService::dispatch`] behind two
@@ -142,6 +154,8 @@ pub enum DomainEvent {
         task_id: TaskId,
         /// The agent that owns completion delivery.
         owner_agent_id: AgentId,
+        /// Rendezvous context when this terminal task is a headless ask.
+        rendezvous: Option<RendezvousContext>,
     },
     /// A first-class background task failed.
     BackgroundTaskFailed {
@@ -151,6 +165,8 @@ pub enum DomainEvent {
         task_id: TaskId,
         /// The agent that owns completion delivery.
         owner_agent_id: AgentId,
+        /// Rendezvous context when this terminal task is a headless ask.
+        rendezvous: Option<RendezvousContext>,
     },
     /// A first-class background task was cancelled.
     BackgroundTaskCancelled {
@@ -160,6 +176,8 @@ pub enum DomainEvent {
         task_id: TaskId,
         /// The agent that owns completion delivery.
         owner_agent_id: AgentId,
+        /// Rendezvous context when this terminal task is a headless ask.
+        rendezvous: Option<RendezvousContext>,
     },
     /// A first-class background task has a terminal result not yet delivered.
     BackgroundTaskCompletionDeliveryPending {

crates/domain/src/lib.rs

@@ -76,6 +76,7 @@ mod validation;
 // ---------------------------------------------------------------------------
 
 pub use error::DomainError;
+pub use events::RendezvousContext;
 
 pub use ids::{
     AgentId, IssueId, LayoutId, LocalModelServerId, NodeId, ProfileId, ProjectId, RuntimeAgentKey,