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

scripts/apply_settings_maintenance.py

@@ -0,0 +1,35 @@
+"""对 SQLite settings 表执行维护 SQL（见 db_optimize_settings.sql）。
+
+使用当前应用配置的数据库路径（app.core.db.DB_PATH）。pytest 使用 PROXYPOOL_DB_PATH
+指向 db/proxies.test.sqlite，勿在生产库路径上误跑测试夹具。
+"""
+import asyncio
+import os
+import sys
+
+# 保证可 import app
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+async def main() -> None:
+    from app.core.db import DB_PATH, ensure_db_dir
+    import aiosqlite
+
+    sql_path = os.path.join(os.path.dirname(__file__), "db_optimize_settings.sql")
+    with open(sql_path, encoding="utf-8") as f:
+        script = f.read()
+
+    ensure_db_dir()
+    if not os.path.isfile(DB_PATH):
+        print(f"数据库不存在，跳过: {DB_PATH}")
+        return
+
+    async with aiosqlite.connect(DB_PATH) as db:
+        await db.executescript(script)
+        await db.commit()
+    print(f"已执行设置维护: {DB_PATH}")
+    print("请重启应用或在 WebUI 保存一次设置以使并发/超时生效。")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())