fix: 修复设置系统脱节、队列计数漂移、资源泄露等全量问题

- 统一设置系统：create_scheduler_service 读取 DB 设置覆盖默认值
- 修复 ProxyRepository.update_score 误删所有无效代理的 SQL
- ValidationQueue：修复 Worker 计数漂移与启动恢复任务饿死
- SchedulerService：移除 drain() 阻塞，主循环可正常响应 stop
- TaskService：在调度器周期内自动清理过期任务，防止内存泄漏
- lifespan/conftest：规范关闭顺序，消除 Event loop closed 警告
- Repository：异常日志增加 exc_info，今日新增按 created_at 统计
- ValidatorService：防止 HTTP session 重复关闭，移除 SOCKS 多余 close
- 前端：补全 pluginsStore.isEmpty，ProxyList 最低分数上限改为 100
- 删除 config.py 中冗余的 cors_origins_list property

app/plugins/base.py

@@ -2,7 +2,7 @@
 import random
 import asyncio
 import httpx
-from typing import List
+from typing import List, Optional
 from app.core.plugin_system import BaseCrawlerPlugin
 
 
@@ -19,6 +19,7 @@ class BaseHTTPPlugin(BaseCrawlerPlugin):
         ]
         self.urls: List[str] = []
         self.current_url: str = ""
+        self._client: Optional[httpx.AsyncClient] = None
 
     def get_headers(self) -> dict:
         return {
@@ -28,30 +29,38 @@ class BaseHTTPPlugin(BaseCrawlerPlugin):
             "Connection": "keep-alive",
         }
 
+    def _get_client(self) -> httpx.AsyncClient:
+        """获取或创建复用的 AsyncClient"""
+        if self._client is None or self._client.is_closed:
+            transport = httpx.AsyncHTTPTransport(retries=0)
+            self._client = httpx.AsyncClient(
+                transport=transport,
+                follow_redirects=True,
+            )
+        return self._client
+
     async def fetch(self, url: str, timeout: float = 15.0, retries: int = 2) -> str:
         """异步抓取指定 URL 的 HTML 内容"""
         from app.core.log import logger
-        headers = self.get_headers()
-        transport = httpx.AsyncHTTPTransport(retries=0)
+        client = self._get_client()
         for attempt in range(retries):
-            async with httpx.AsyncClient(headers=headers, transport=transport, follow_redirects=True) as client:
-                try:
-                    response = await client.get(url, timeout=timeout)
-                    if response.status_code == 200:
-                        content = response.content
-                        encoding = response.encoding
-                        if encoding == "utf-8" or not encoding:
-                            try:
-                                return content.decode("utf-8")
-                            except UnicodeDecodeError:
-                                return content.decode("gbk", errors="ignore")
-                        return content.decode(encoding, errors="ignore")
-                    else:
-                        logger.warning(f"Fetch {url} returned status {response.status_code}")
-                except Exception as e:
-                    logger.warning(f"Fetch {url} failed (attempt {attempt + 1}/{retries}): {e}")
-                if attempt < retries - 1:
-                    await asyncio.sleep(random.uniform(1, 3))
+            try:
+                response = await client.get(url, headers=self.get_headers(), timeout=timeout)
+                if response.status_code == 200:
+                    content = response.content
+                    encoding = response.encoding
+                    if encoding == "utf-8" or not encoding:
+                        try:
+                            return content.decode("utf-8")
+                        except UnicodeDecodeError:
+                            return content.decode("gbk", errors="ignore")
+                    return content.decode(encoding, errors="ignore")
+                else:
+                    logger.warning(f"Fetch {url} returned status {response.status_code}")
+            except Exception as e:
+                logger.warning(f"Fetch {url} failed (attempt {attempt + 1}/{retries}): {e}")
+            if attempt < retries - 1:
+                await asyncio.sleep(random.uniform(1, 3))
         return ""
 
     async def fetch_all(self, urls: List[str], timeout: float = 15.0) -> List[str]:
@@ -64,3 +73,9 @@ class BaseHTTPPlugin(BaseCrawlerPlugin):
 
         tasks = [_fetch_limited(url) for url in urls]
         return await asyncio.gather(*tasks)
+
+    async def close(self):
+        """关闭复用的 HTTP 客户端"""
+        if self._client and not self._client.is_closed:
+            await self._client.aclose()
+            self._client = None