Fix datetime deprecation warnings in Phase 8 modules

- Update all datetime.utcnow() to datetime.now(UTC) for Python 3.12+ compatibility
- Update all datetime.utcfromtimestamp() to datetime.fromtimestamp(..., UTC)
- Fix dataclass default_factory to use lambda: datetime.now(UTC)
- Update auth, audit, billing, and realtime modules
- Add UTC import from datetime module
- Update pytest configuration to include pytest-asyncio
- All 28 Phase 8 enterprise tests pass with no warnings

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

ontology_platform/ont_platform/realtime/websocket.py

@@ -0,0 +1,129 @@
+"""WebSocket 연결 관리 (Phase 8).
+
+기능:
+- 클라이언트 연결 관리
+- 조직별 격리
+- 메시지 브로드캐스트
+"""
+
+import logging
+from typing import Dict, Set, Optional
+from fastapi import WebSocket
+
+logger = logging.getLogger(__name__)
+
+
+class ConnectionManager:
+    """WebSocket 연결 관리."""
+
+    def __init__(self):
+        """초기화."""
+        # org_id → {WebSocket 객체들}
+        self.active_connections: Dict[str, Set[WebSocket]] = {}
+        # WebSocket → org_id (역 매핑)
+        self.connection_to_org: Dict[WebSocket, str] = {}
+
+    async def connect(self, org_id: str, websocket: WebSocket) -> None:
+        """클라이언트 연결.
+
+        Args:
+            org_id: 조직 ID
+            websocket: WebSocket 연결
+        """
+        await websocket.accept()
+
+        if org_id not in self.active_connections:
+            self.active_connections[org_id] = set()
+
+        self.active_connections[org_id].add(websocket)
+        self.connection_to_org[websocket] = org_id
+
+        logger.info(f"WebSocket connected for org {org_id}")
+
+    async def disconnect(self, websocket: WebSocket) -> None:
+        """클라이언트 연결 해제.
+
+        Args:
+            websocket: WebSocket 연결
+        """
+        org_id = self.connection_to_org.get(websocket)
+
+        if org_id:
+            if org_id in self.active_connections:
+                self.active_connections[org_id].discard(websocket)
+
+                if not self.active_connections[org_id]:
+                    del self.active_connections[org_id]
+
+            del self.connection_to_org[websocket]
+
+            logger.info(f"WebSocket disconnected for org {org_id}")
+
+    async def broadcast(self, org_id: str, message: dict) -> int:
+        """조직의 모든 클라이언트에게 메시지 브로드캐스트.
+
+        Args:
+            org_id: 조직 ID
+            message: 전송할 메시지
+
+        Returns:
+            전송 성공 수
+        """
+        if org_id not in self.active_connections:
+            return 0
+
+        disconnected = set()
+        sent_count = 0
+
+        for connection in self.active_connections[org_id]:
+            try:
+                await connection.send_json(message)
+                sent_count += 1
+            except Exception as e:
+                logger.warning(f"Failed to send message: {e}")
+                disconnected.add(connection)
+
+        # 연결 끊긴 클라이언트 제거
+        for connection in disconnected:
+            await self.disconnect(connection)
+
+        return sent_count
+
+    async def broadcast_all(self, message: dict) -> int:
+        """모든 클라이언트에게 메시지 브로드캐스트.
+
+        Args:
+            message: 전송할 메시지
+
+        Returns:
+            전송 성공 수
+        """
+        total_sent = 0
+
+        for org_id in list(self.active_connections.keys()):
+            sent = await self.broadcast(org_id, message)
+            total_sent += sent
+
+        return total_sent
+
+    def get_connection_count(self, org_id: Optional[str] = None) -> int:
+        """연결 수 조회.
+
+        Args:
+            org_id: 조직 ID (None이면 전체)
+
+        Returns:
+            연결 수
+        """
+        if org_id is None:
+            return sum(len(connections) for connections in self.active_connections.values())
+
+        return len(self.active_connections.get(org_id, set()))
+
+    def get_org_ids(self) -> list:
+        """활성 조직 ID 리스트 조회.
+
+        Returns:
+            조직 ID 리스트
+        """
+        return list(self.active_connections.keys())