feat(domain,application,infrastructure,backend,web-server,app-tauri,frontend): persistance et reprise des conversations de CLI custom par agent — index durable <projet>/.ideai/conversations/custom-index.json borné aux conversations non vides par agent (conversation_id logique, titre dérivé de la première invite, created/updated_at_ms), port CustomConversationIndex + adaptateur FsCustomConversationIndex, persistence des messages utilisateur et finals agent dans le log de conversation existant, DTO/commandes app-tauri et routes web-server pour lister/rouvrir, CustomAgentChatView: ouverture par défaut sur une nouvelle conversation, menu reprise d'une conversation passée ou nouvelle conversation, replay de l'historique sauvegardé (user+finals) à la réouverture, affichage normal des nouveaux messages après reprise, /clean ouvre une nouvelle conversation, aucune entrée créée si la conversation courante est vide, injection de l'historique dans le contexte agent différée au premier nouveau message après reprise — #363 (QA verte: git diff --check, cargo fmt --all -- --check, cargo tests ciblés infrastructure/application/web-server/app-tauri/backend, npm run typecheck, tests frontend ciblés et CustomAgentChatView, npm run build)

crates/application/tests/cancel_agent_chat.rs

@@ -74,6 +74,40 @@ fn id<T>(value: u128, make: impl FnOnce(Uuid) -> T) -> T {
     make(Uuid::from_u128(value))
 }
 
+#[test]
+fn custom_conversation_binding_keeps_logical_id_and_consumes_resume_once() {
+    let session_id = id(1, SessionId::from_uuid);
+    let project_id = id(2, ProjectId::from_uuid);
+    let agent_id = id(3, AgentId::from_uuid);
+    let node_id = id(4, NodeId::from_uuid);
+    let conversation_id = domain::ConversationId::from_uuid(Uuid::from_u128(5));
+    let sessions = StructuredSessions::new();
+    sessions.insert_in_project(
+        project_id,
+        Arc::new(FakeSession::new(session_id, [])),
+        agent_id,
+        node_id,
+    );
+
+    sessions.bind_custom_conversation(
+        session_id,
+        conversation_id,
+        Some("bounded handoff".to_owned()),
+    );
+
+    assert_eq!(
+        sessions.custom_conversation_id(&session_id),
+        Some(conversation_id)
+    );
+    assert_eq!(
+        sessions
+            .take_pending_resume_preamble(&session_id)
+            .as_deref(),
+        Some("bounded handoff")
+    );
+    assert_eq!(sessions.take_pending_resume_preamble(&session_id), None);
+}
+
 struct TurnAccounting {
     state: Mutex<AgentBusyState>,
     cancelled: Mutex<Vec<(RuntimeAgentKey, TicketId)>>,

crates/application/tests/structured_launch_d3.rs

@@ -918,6 +918,44 @@ async fn global_idea_cli_preference_applies_to_a_new_human_launch() {
     assert_eq!(f.pty.spawn_count(), 0);
 }
 
+#[tokio::test]
+async fn explicit_custom_chat_gets_a_fresh_logical_conversation_without_persisting_it() {
+    let f = launch_fixture(
+        structured_profile(pid(9)),
+        FakeFactory::new(500, Some("engine-conv")),
+    );
+    let mut input = launch_input(f.agent.id);
+    input.require_structured = true;
+
+    let output = f.launch.execute(input).await.unwrap();
+    let assigned = output
+        .assigned_conversation_id
+        .as_deref()
+        .and_then(|raw| Uuid::parse_str(raw).ok())
+        .map(ConversationId::from_uuid)
+        .expect("fresh logical conversation id");
+
+    assert_eq!(assigned, ConversationId::from_uuid(Uuid::from_u128(1)));
+    assert_ne!(
+        assigned,
+        ConversationId::for_project_pair(
+            project_id(),
+            ConversationParty::User,
+            ConversationParty::agent(f.agent.id),
+        ),
+        "each explicit custom chat is a distinct logical thread"
+    );
+    assert_eq!(
+        f.structured.custom_conversation_id(&sid(500)),
+        Some(assigned)
+    );
+    assert_eq!(
+        f.structured.take_pending_resume_preamble(&sid(500)),
+        None,
+        "a fresh chat has no resume context"
+    );
+}
+
 #[tokio::test]
 async fn explicit_native_tui_overrides_the_global_idea_cli_preference() {
     let f = launch_fixture_with_preference(DefaultAgentTerminalInterface::IdeaCli);