feat: Add presence heartbeat for Matrix online status

- matrix-gateway: POST /internal/matrix/presence/online endpoint
- usePresenceHeartbeat hook with activity tracking
- Auto away after 5 min inactivity
- Offline on page close/visibility change
- Integrated in MatrixChatRoom component

services/dao-service/auth_client.py

@@ -0,0 +1,32 @@
+"""
+Auth Client — Get actor identity from auth-service
+Phase 8: DAO Dashboard
+"""
+from fastapi import HTTPException, Header
+from typing import Optional
+import httpx
+import os
+
+AUTH_SERVICE_URL = os.getenv("AUTH_SERVICE_URL", "http://localhost:7011")
+
+async def get_actor_from_token(authorization: Optional[str] = Header(None)) -> dict:
+    """
+    Get ActorIdentity from auth-service
+    Returns actor dict or raises 401
+    """
+    if not authorization or not authorization.startswith("Bearer "):
+        raise HTTPException(status_code=401, detail="Missing or invalid authorization header")
+    
+    token = authorization.replace("Bearer ", "")
+    
+    async with httpx.AsyncClient() as client:
+        try:
+            response = await client.get(
+                f"{AUTH_SERVICE_URL}/auth/me",
+                headers={"Authorization": f"Bearer {token}"}
+            )
+            response.raise_for_status()
+            return response.json()
+        except httpx.HTTPError:
+            raise HTTPException(status_code=401, detail="Invalid or expired token")
+