feat: fpw plugins, validation/crawl perf, WS stats, test DB isolation

- Add Free_Proxy_Website-style fpw_* plugins and register them
- Per-plugin crawl timeout (crawl_timeout_seconds=120); remove global crawl_timeout setting
- Validator: fix connect vs total timeout on save; SOCKS session LRU cache; drop redundant semaphore
- Validation handler uses single DB connection; batch upsert after crawl; WorkerPool put_nowait
- Remove unused max_retries from settings API/UI; settings maintenance SQL + init_db cleanup of deprecated keys
- WebSocket dashboard stats; ProxyList pool_filter and API alignment
- POST /api/proxies/delete-one for IPv6-safe deletes; task poll stops on 404
- pytest uses PROXYPOOL_DB_PATH=db/proxies.test.sqlite so tests do not wipe production DB
- .gitignore: explicit proxies.test.sqlite patterns; fix plugin_service ValidationException import

Made-with: Cursor

app/api/routes/ws.py

@@ -0,0 +1,32 @@
+"""WebSocket 实时推送"""
+import json
+
+from fastapi import APIRouter, WebSocket
+from starlette.websockets import WebSocketDisconnect
+
+from app.services.dashboard_stats import get_dashboard_stats
+
+router = APIRouter(prefix="/api", tags=["websocket"])
+
+
+@router.websocket("/ws")
+async def websocket_dashboard(websocket: WebSocket):
+    app = websocket.app
+    await websocket.accept()
+    manager = app.state.ws_manager
+    await manager.connect(websocket)
+    try:
+        stats = await get_dashboard_stats(app.state.scheduler.running)
+        await websocket.send_json({"type": "stats", "data": stats})
+        while True:
+            raw = await websocket.receive_text()
+            try:
+                msg = json.loads(raw)
+            except json.JSONDecodeError:
+                continue
+            if msg.get("type") == "ping":
+                await websocket.send_json({"type": "pong"})
+    except WebSocketDisconnect:
+        pass
+    finally:
+        await manager.disconnect(websocket)