feat: Implement Matrix Rooms Bridge

- MATRIX_ROOMS_BRIDGE_SPEC.md documentation
- Migration 012: Add matrix_room_id/alias to city_rooms
- Matrix Gateway service (port 7025)
- City-service: auto-create Matrix rooms on room creation
- Backfill endpoint for existing rooms
- API returns matrix_room_id/alias in room responses

services/city-service/models_city.py

@@ -0,0 +1,109 @@
+"""
+Pydantic Models для City Backend
+"""
+
+from pydantic import BaseModel, Field
+from typing import Optional, List
+from datetime import datetime
+
+
+# =============================================================================
+# City Rooms
+# =============================================================================
+
+class CityRoomBase(BaseModel):
+    slug: str
+    name: str
+    description: Optional[str] = None
+
+
+class CityRoomCreate(CityRoomBase):
+    pass
+
+
+class CityRoomRead(CityRoomBase):
+    id: str
+    is_default: bool
+    created_at: datetime
+    created_by: Optional[str] = None
+    members_online: int = 0
+    last_event: Optional[str] = None
+    # Matrix integration
+    matrix_room_id: Optional[str] = None
+    matrix_room_alias: Optional[str] = None
+
+
+# =============================================================================
+# City Room Messages
+# =============================================================================
+
+class CityRoomMessageBase(BaseModel):
+    body: str = Field(..., min_length=1, max_length=10000)
+
+
+class CityRoomMessageCreate(CityRoomMessageBase):
+    pass
+
+
+class CityRoomMessageRead(CityRoomMessageBase):
+    id: str
+    room_id: str
+    author_user_id: Optional[str] = None
+    author_agent_id: Optional[str] = None
+    username: Optional[str] = "Anonymous"  # Для frontend
+    created_at: datetime
+
+
+# =============================================================================
+# City Room Detail (з повідомленнями)
+# =============================================================================
+
+class CityRoomDetail(CityRoomRead):
+    messages: List[CityRoomMessageRead] = []
+    online_members: List[str] = []  # user_ids
+
+
+# =============================================================================
+# City Feed Events
+# =============================================================================
+
+class CityFeedEventRead(BaseModel):
+    id: str
+    kind: str  # 'room_message', 'agent_reply', 'system', 'dao_event'
+    room_id: Optional[str] = None
+    user_id: Optional[str] = None
+    agent_id: Optional[str] = None
+    payload: dict
+    created_at: datetime
+
+
+# =============================================================================
+# Presence
+# =============================================================================
+
+class PresenceUpdate(BaseModel):
+    user_id: str
+    status: str  # 'online', 'offline', 'away'
+    last_seen: Optional[datetime] = None
+
+
+class PresenceBulkUpdate(BaseModel):
+    users: List[PresenceUpdate]
+
+
+# =============================================================================
+# WebSocket Messages
+# =============================================================================
+
+class WSRoomMessage(BaseModel):
+    event: str  # 'room.message', 'room.join', 'room.leave'
+    room_id: Optional[str] = None
+    user_id: Optional[str] = None
+    message: Optional[CityRoomMessageRead] = None
+
+
+class WSPresenceMessage(BaseModel):
+    event: str  # 'presence.heartbeat', 'presence.update'
+    user_id: str
+    status: Optional[str] = None
+