fix: cross-project event flooding + pending accumulation + diff_review brain exclusion

Phase 1: Collector auto-cleanup of auto_resolved/expired pending files after Gateway forwarding
Phase 2: Watcher project filter (only MY sessions emit events) + Collector event forward filter
Phase 3: Extension diff_review excludes brain/ artifact files (task.md, implementation_plan.md)

watcher.py

@@ -40,7 +40,11 @@ class BrainEvent:
 
 
 class BrainEventHandler(FileSystemEventHandler):
-    """Watchdog handler that filters, debounces, and deduplicates brain events."""
+    """Watchdog handler that filters, debounces, and deduplicates brain events.
+
+    Phase 2 FIX: Only emits events for sessions belonging to the current project
+    (Config.PROJECT_NAME), using bridge/register/ files for session→project mapping.
+    """
 
     def __init__(self, event_queue: asyncio.Queue, loop: asyncio.AbstractEventLoop):
         super().__init__()
@@ -49,6 +53,10 @@ class BrainEventHandler(FileSystemEventHandler):
         self._last_events: dict[str, float] = {}       # path -> timestamp (debounce)
         self._content_hashes: dict[str, str] = {}       # path -> md5 hash (dedup)
         self._known_sessions: set[str] = set()
+        # Phase 2: project filter
+        self._session_project_map: dict[str, str] = {}  # conv_id → project_name
+        self._project_map_ts: float = 0                  # last load timestamp
+        self._PROJECT_MAP_TTL: float = 60.0              # reload every 60s
         self._initialize_known_sessions()
 
     def _initialize_known_sessions(self):
@@ -77,6 +85,47 @@ class BrainEventHandler(FileSystemEventHandler):
                 f"pre-loaded {hash_count} content hashes"
             )
 
+    def _load_session_project_map(self) -> dict[str, str]:
+        """Load session→project mapping from bridge/register/ files (cached)."""
+        now = time.time()
+        if now - self._project_map_ts < self._PROJECT_MAP_TTL:
+            return self._session_project_map
+
+        import json
+        register_dir = Config.BRAIN_PATH.parent / "bridge" / "register"
+        if not register_dir.exists():
+            self._project_map_ts = now
+            return self._session_project_map
+
+        new_map: dict[str, str] = {}
+        for f in register_dir.glob("*.json"):
+            try:
+                data = json.loads(f.read_text(encoding="utf-8-sig"))
+                conv_id = data.get("conversation_id", "")
+                project = data.get("project_name", "")
+                if conv_id and project:
+                    new_map[conv_id] = project
+            except (json.JSONDecodeError, OSError):
+                pass
+
+        self._session_project_map = new_map
+        self._project_map_ts = now
+        return self._session_project_map
+
+    def _is_my_session(self, conv_id: str) -> bool:
+        """Check if a session belongs to the current project.
+
+        Returns True for:
+        - Sessions registered to Config.PROJECT_NAME
+        - Unknown sessions (not in any register file — allow to avoid blocking)
+        Returns False for sessions registered to OTHER projects.
+        """
+        session_map = self._load_session_project_map()
+        project = session_map.get(conv_id)
+        if project is None:
+            return True  # Unknown → allow (newly started, not yet registered)
+        return project == Config.PROJECT_NAME
+
     def dispatch(self, event: FileSystemEvent):
         """Early filter: skip events for files/dirs we don't care about.
 
@@ -169,6 +218,10 @@ class BrainEventHandler(FileSystemEventHandler):
         if not conv_id:
             return
 
+        # Phase 2 FIX: only emit events for MY project's sessions
+        if not self._is_my_session(conv_id):
+            return
+
         # Exclude files in .system_generated subdirectory (AG internal logs)
         try:
             relative = path.relative_to(Config.BRAIN_PATH / conv_id)