fix: fast-idle session on openclaw.cache-ttl (turn complete signal)

Previously the daemon waited IDLE_TIMEOUT_S (60s) after the last file
change before marking a session complete. But the JSONL file is kept
open by the gateway indefinitely, so file inactivity was never reliable.

Fix: detect the 'openclaw.cache-ttl' custom record which the gateway
emits after every completed assistant turn. When pendingToolCalls == 0,
start a 3-second grace timer instead of the full 60s idle timeout.

Result: live status clears within ~3 seconds of the agent's final reply
instead of lingering for 60+ seconds (or indefinitely on active sessions).

Fixes: session stays 'active' long after work is done

src/status-watcher.js

@@ -379,6 +379,21 @@ class StatusWatcher extends EventEmitter {
       return;
     }
 
+    // OpenClaw cache-ttl custom record: reliable "turn complete" signal.
+    // Emitted after every assistant turn. Use it to fast-idle the session
+    // instead of waiting the full IDLE_TIMEOUT_S.
+    if (record.type === 'custom' && record.customType === 'openclaw.cache-ttl') {
+      if (state.pendingToolCalls === 0) {
+        // Turn is done — fast-idle: fire idle check after a short grace period (3s)
+        // to allow any trailing writes to flush before marking complete.
+        if (state.idleTimer) clearTimeout(state.idleTimer);
+        state.idleTimer = setTimeout(() => {
+          this._checkIdle(sessionKey);
+        }, 3000);
+      }
+      return;
+    }
+
     // Legacy format fallback (for compatibility)
     var legacyType = record.type;