refactor: 아키텍처 수정 — 동기HTTP→aiohttp + 연결 모니터링 + 재시도큐

#1 동기 HTTP → async aiohttp (Critical)
  - RemoteTransport: urllib.request → aiohttp.ClientSession
  - 모든 HTTP 요청이 non-blocking으로 전환
  - 이벤트 루프 블로킹 문제 해결

#2 연결 상태 모니터링
  - RemoteTransport: connected 플래그 + 연속 실패 카운터
  - Collector: 30초마다 health check → 실패 시 경고 로그
  - 연결 복구 시 '✅ Gateway connected' 메시지

#3 실패 재시도 큐
  - RemoteTransport: _retry_queue (최대 100건)
  - POST 실패 시 큐에 저장, 연결 복구 후 자동 재전송
  - Collector: 10초마다 retry flush

collector.py

@@ -69,14 +69,17 @@ class CollectorBridge:
             self._poll_commands_loop(),
             self._forward_chat_snapshots_loop(),
             self._forward_registrations_loop(),
+            self._health_check_loop(),
+            self._retry_flush_loop(),
         ]
         if self.event_queue:
             tasks.append(self._forward_events_loop())
         await asyncio.gather(*tasks)
 
     async def stop(self):
-        """Stop the Collector."""
+        """Stop the Collector and close HTTP session."""
         self._running = False
+        await self.remote.close()
         logger.info("[COLLECTOR] stopped")
 
     # ─── Forward local pending → Gateway ───
@@ -114,7 +117,7 @@ class CollectorBridge:
                         continue  # Skip pre-existing files from before startup
 
                     # Forward to Gateway (new or updated)
-                    self.remote.write_json("pending", fname, data)
+                    await self.remote.awrite_json("pending", fname, data)
                     self._forwarded_pending.add(rid)
                     self._pending_hashes[rid] = content_hash
 
@@ -143,7 +146,7 @@ class CollectorBridge:
             try:
                 # Check each forwarded pending for a response
                 for rid in list(self._forwarded_pending):
-                    data = self.remote.read_json("response", f"{rid}.json")
+                    data = await self.remote.aread_json("response", f"{rid}.json")
                     if data is None or data.get("waiting"):
                         continue
 
@@ -166,7 +169,7 @@ class CollectorBridge:
         """Poll Gateway for commands and write them locally for Extension."""
         while self._running:
             try:
-                commands = self.remote.poll_commands(self.project_name)
+                commands = await self.remote.apoll_commands(self.project_name)
                 for cmd in commands:
                     cmd_id = cmd.get("id", str(int(time.time() * 1000)))
                     fname = f"{cmd_id}.json"
@@ -192,7 +195,7 @@ class CollectorBridge:
                             project = data.get("project_name", self.project_name)
                             content = data.get("content", "")
                             if content:
-                                self.remote.send_chat(project, content)
+                                await self.remote.asend_chat(project, content)
                                 logger.info(f"[COLLECTOR] → Gateway: chat snapshot len={len(content)}")
                             f.unlink()  # Cleanup after forwarding
                         except (json.JSONDecodeError, OSError) as e:
@@ -219,7 +222,7 @@ class CollectorBridge:
                             conv_id = data.get("conversation_id", "")
                             project = data.get("project_name", "")
                             if conv_id and project:
-                                self.remote.register_session(conv_id, project)
+                                await self.remote.aregister_session(conv_id, project)
                                 forwarded_regs.add(f.name)
                                 logger.info(f"[COLLECTOR] → Gateway: register {conv_id[:8]} → {project}")
                         except (json.JSONDecodeError, OSError) as e:
@@ -246,9 +249,33 @@ class CollectorBridge:
                     "content": event.content,
                     "timestamp": event.timestamp,
                 }
-                self.remote._request("POST", "/api/event", event_data)
+                await self.remote.asend_event(event_data)
                 logger.info(f"[COLLECTOR] → Gateway: event {event.event_type.value} {event.file_name}")
             except asyncio.TimeoutError:
                 continue
             except Exception as e:
                 logger.error(f"[COLLECTOR] forward_event error: {e}")
+
+    # ─── Health check ───
+
+    async def _health_check_loop(self):
+        """Periodically check Gateway connectivity."""
+        while self._running:
+            try:
+                ok = await self.remote.health_check()
+                if not ok and self.remote.connected:
+                    logger.warning("[COLLECTOR] ❌ Gateway health check failed")
+            except Exception:
+                pass
+            await asyncio.sleep(30)
+
+    # ─── Retry flush ───
+
+    async def _retry_flush_loop(self):
+        """Periodically flush failed request retry queue."""
+        while self._running:
+            try:
+                await self.remote.flush_retry_queue()
+            except Exception as e:
+                logger.error(f"[COLLECTOR] retry flush error: {e}")
+            await asyncio.sleep(10)