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/core/config.py

@@ -1,6 +1,7 @@
 """全局配置 - 使用 Pydantic Settings 支持环境变量和 .env 文件"""
 import os
 from typing import List
+from pydantic import AliasChoices, Field
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
 
@@ -11,8 +12,11 @@ class Settings(BaseSettings):
         extra="ignore",
     )
 
-    # 数据库配置
-    db_path: str = "db/proxies.sqlite"
+    # 数据库配置（环境变量 PROXYPOOL_DB_PATH 优先，供 pytest 与生产隔离）
+    db_path: str = Field(
+        default="db/proxies.sqlite",
+        validation_alias=AliasChoices("PROXYPOOL_DB_PATH", "DB_PATH", "db_path"),
+    )
 
     # API 服务配置
     host: str = "127.0.0.1"
@@ -31,6 +35,9 @@ class Settings(BaseSettings):
     log_level: str = "INFO"
     log_dir: str = "logs"
 
+    # WebSocket：统计广播间隔（秒）；无连接时不查库
+    ws_stats_interval_seconds: int = 1
+
     # 导出配置
     export_max_records: int = 10000