feat(orchestrator): create_skill action + wire per-project watchers (§14.3)

- domain: OrchestratorCommand::CreateSkill with optional scope field
  (defaults to Project, case-insensitive, UnknownScope on bad value)
- application: dispatch CreateSkill through the CreateSkill use case
- app-tauri: build OrchestratorService and start/stop per-project request
  watchers on open/create/close_project (ensure/stop_orchestrator_watch)
- tests: domain validation, service dispatch, infra watcher e2e,
  app-tauri wiring lifecycle (idempotent, isolated, stop)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/features/agents/useAgents.ts

@@ -64,7 +64,7 @@ function describe(e: unknown): string {
 }
 
 export function useAgents(projectId: string): AgentsViewModel {
-  const { agent, profile } = useGateways();
+  const { agent, profile, system } = useGateways();
 
   const [agents, setAgents] = useState<Agent[]>([]);
   const [selectedAgentId, setSelectedAgentId] = useState<string | null>(null);
@@ -95,6 +95,32 @@ export function useAgents(projectId: string): AgentsViewModel {
     void refresh();
   }, [refresh]);
 
+  // Live refresh: the agents list is otherwise only reloaded on mount or after a
+  // UI-driven CRUD. An agent created/launched/stopped *out of band* — most
+  // notably by the orchestrator (`spawn_agent`, ARCHITECTURE §14.3) when an AI
+  // delegates agent creation to IdeA — emits `agentLaunched` / `agentExited`.
+  // Subscribing here makes the tab reflect those changes without a manual reload.
+  // `system` may be absent in unit tests that inject a partial gateway set; guard.
+  useEffect(() => {
+    if (!system) return;
+    let unsubscribe: (() => void) | undefined;
+    let cancelled = false;
+    void system
+      .onDomainEvent((event) => {
+        if (event.type === "agentLaunched" || event.type === "agentExited") {
+          void refresh();
+        }
+      })
+      .then((un) => {
+        if (cancelled) un();
+        else unsubscribe = un;
+      });
+    return () => {
+      cancelled = true;
+      unsubscribe?.();
+    };
+  }, [system, refresh]);
+
   const createAgent = useCallback(
     async (name: string, profileId: string, initialContent?: string) => {
       setBusy(true);