fix: persist activity state to metadata so API serves real-time activity

- lifecycle-manager: write detected activity to metadata on each poll
- session-manager: read activity from metadata instead of hardcoding idle
- Fixes: API always returned activity=idle because metadataToSession
  hardcoded it and lifecycle manager never persisted the detected value

packages/core/src/lifecycle-manager.ts

@@ -201,6 +201,15 @@ export function createLifecycleManager(deps: LifecycleManagerDeps): LifecycleMan
         // empty output means the runtime probe failed, not that the agent exited.
         if (terminalOutput) {
           const activity = agent.detectActivity(terminalOutput);
+          console.log("[LIFECYCLE DEBUG] session:", session.id, "activity:", activity, "hasEsc:", /esc to interrupt/i.test(terminalOutput), "terminalLen:", terminalOutput.length);
+          // Persist detected activity to metadata so the API can serve it
+          const projectMetaDir2 = session.projectId
+            ? join(config.dataDir, `${session.projectId}-sessions`)
+            : config.dataDir;
+          const metaDir2 = existsSync(join(projectMetaDir2, session.id))
+            ? projectMetaDir2
+            : config.dataDir;
+          updateMetadata(metaDir2, session.id, { activity });
           if (activity === "waiting_input") return "needs_input";
 
           // Check whether the agent process is still alive. Some agents

packages/core/src/session-manager.ts

@@ -19,6 +19,7 @@ import type {
   SessionId,
   SessionSpawnConfig,
   SessionStatus,
+  ActivityState,
   CleanupResult,
   OrchestratorConfig,
   ProjectConfig,
@@ -106,7 +107,7 @@ function metadataToSession(
     id: sessionId,
     projectId: meta["project"] ?? "",
     status: validateStatus(meta["status"]),
-    activity: "idle",
+    activity: (meta["activity"] as ActivityState) || "idle",
     branch: meta["branch"] || null,
     issueId: meta["issue"] || null,
     pr: meta["pr"]