refactor(backend): optimize database safety, validator performance, and scheduler concurrency

- Fix SQL injection risks in proxy_repo and task_repo
- Atomic acquire_pending with UPDATE ... RETURNING
- Reuse aiohttp ClientSession in ValidatorService
- Replace polling with asyncio.Event in SchedulerService
- Optimize ValidationQueue.drain with asyncio.Condition
- Concurrent plugin crawling with asyncio.gather
- Unify ProxyRaw model import path
- Fix test baseline and remove tracked __pycache__ files

app/services/plugin_service.py

@@ -1,4 +1,5 @@
 """插件业务服务"""
+import asyncio
 from datetime import datetime
 from typing import List, Optional
 from app.core.db import get_db
@@ -108,14 +109,13 @@ class PluginService:
     async def run_all_plugins(self) -> List[ProxyRaw]:
         """执行所有启用插件的爬取"""
         all_results: List[ProxyRaw] = []
-        for plugin in registry.list_plugins():
-            if not plugin.enabled:
+        tasks = [self.run_plugin(plugin.name) for plugin in registry.list_plugins() if plugin.enabled]
+        results_list = await asyncio.gather(*tasks, return_exceptions=True)
+        for results in results_list:
+            if isinstance(results, Exception):
+                logger.error(f"Run all plugins error: {results}")
                 continue
-            try:
-                results = await self.run_plugin(plugin.name)
-                all_results.extend(results)
-            except Exception as e:
-                logger.error(f"Run all plugins error at {plugin.name}: {e}")
+            all_results.extend(results)
         # 去重
         seen = set()
         unique = []