feat(api): add backend

routes and WebSockets

services/api/app/ws/manager.py

@@ -0,0 +1,39 @@
+from __future__ import annotations
+
+import asyncio
+from typing import Any
+from fastapi import WebSocket
+
+
+class ConnectionManager:
+    def __init__(self) -> None:
+        self._connections: set[WebSocket] = set()
+        self._lock = asyncio.Lock()
+
+    async def connect(self, ws: WebSocket) -> None:
+        await ws.accept()
+        async with self._lock:
+            self._connections.add(ws)
+
+    async def disconnect(self, ws: WebSocket) -> None:
+        async with self._lock:
+            self._connections.discard(ws)
+
+    async def broadcast_json(self, payload: dict[str, Any]) -> None:
+        async with self._lock:
+            conns = list(self._connections)
+
+        to_remove: list[WebSocket] = []
+        for ws in conns:
+            try:
+                await ws.send_json(payload)
+            except Exception:
+                to_remove.append(ws)
+
+        if to_remove:
+            async with self._lock:
+                for ws in to_remove:
+                    self._connections.discard(ws)
+
+
+manager = ConnectionManager()