feat(api): tcp driver registry, identify, preset push delivery

- Track Wi-Fi TCP clients, liveness pings, disconnect broadcast, bind errors via gather\n- Device list/get include connected; POST identify with __identify preset\n- Presets push/send delivery helpers; bump led-driver hello type

Made-with: Cursor

src/util/device_status_broadcaster.py

@@ -0,0 +1,52 @@
+"""Push Wi-Fi TCP connect/disconnect updates to browser WebSocket clients."""
+
+import json
+import threading
+from typing import Any, Set
+
+# Threading lock: safe across asyncio tasks and avoids binding asyncio.Lock to the wrong loop.
+_clients_lock = threading.Lock()
+_clients: Set[Any] = set()
+
+
+async def register_device_status_ws(ws: Any) -> None:
+    with _clients_lock:
+        _clients.add(ws)
+
+
+async def unregister_device_status_ws(ws: Any) -> None:
+    with _clients_lock:
+        _clients.discard(ws)
+
+
+async def broadcast_device_tcp_status(ip: str, connected: bool) -> None:
+    from models.tcp_clients import normalize_tcp_peer_ip
+
+    ip = normalize_tcp_peer_ip(ip)
+    if not ip:
+        return
+    msg = json.dumps({"type": "device_tcp", "ip": ip, "connected": bool(connected)})
+    with _clients_lock:
+        targets = list(_clients)
+    dead = []
+    for ws in targets:
+        try:
+            await ws.send(msg)
+        except Exception as exc:
+            dead.append(ws)
+            print(f"[device_status_broadcaster] ws.send failed: {exc!r}")
+    if dead:
+        with _clients_lock:
+            for ws in dead:
+                _clients.discard(ws)
+
+
+async def broadcast_device_tcp_snapshot_to(ws: Any) -> None:
+    from models import tcp_clients as tcp
+
+    ips = tcp.list_connected_ips()
+    msg = json.dumps({"type": "device_tcp_snapshot", "connected_ips": ips})
+    try:
+        await ws.send(msg)
+    except Exception as exc:
+        print(f"[device_status_broadcaster] snapshot send failed: {exc!r}")