feat(collector): brain event 중계 추가 — Watcher 이벤트를 Gateway로 전달

- collector.py: _forward_events_loop — BrainEvent를 JSON으로 serialize하여 /api/event POST
- gateway.py: /api/event 엔드포인트 — 수신한 이벤트를 bot event_queue에 주입
- main.py: event_queue를 CollectorBridge에 전달

이제 task.md, implementation_plan, walkthrough 변경사항이 Collector→Gateway→Discord 경로로 전달됨

gateway.py

@@ -20,6 +20,7 @@ import asyncio
 import json
 import time
 import logging
+from pathlib import Path
 from aiohttp import web
 
 logger = logging.getLogger(__name__)
@@ -47,6 +48,7 @@ class GatewayAPI:
         self.app.router.add_post("/api/chat", self._post_chat)
         self.app.router.add_post("/api/register", self._post_register)
         self.app.router.add_get("/api/commands/{project}", self._get_commands)
+        self.app.router.add_post("/api/event", self._post_event)
 
     # ─── Auth Middleware ───
 
@@ -184,6 +186,35 @@ class GatewayAPI:
             self._commands[project] = []
         self._commands[project].append(command)
 
+    # ─── Brain Events (Collector → Gateway → Discord) ───
+
+    async def _post_event(self, request: web.Request) -> web.Response:
+        """Collector pushes a brain event (file change) for relay to Discord."""
+        try:
+            data = await request.json()
+            from watcher import BrainEvent, EventType
+
+            event_type_str = data.get("event_type", "file_changed")
+            event_type = EventType(event_type_str)
+
+            event = BrainEvent(
+                event_type=event_type,
+                conversation_id=data.get("conversation_id", ""),
+                file_name=data.get("file_name", ""),
+                file_path=Path(data["file_path"]) if data.get("file_path") else None,
+                content=data.get("content", ""),
+                timestamp=data.get("timestamp", time.time()),
+            )
+
+            # Inject into bot's event queue (same path as local mode)
+            await self.bot.event_queue.put(event)
+            logger.info(f"[GATEWAY] event received: {event_type_str} {event.file_name} conv={event.conversation_id[:8]}")
+
+            return web.json_response({"ok": True})
+        except Exception as e:
+            logger.error(f"[GATEWAY] event error: {e}")
+            return web.json_response({"ok": False, "error": str(e)}, status=400)
+
     # ─── Run ───
 
     async def start(self):