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/validator_service.py

@@ -25,8 +25,24 @@ class ValidatorService:
     ):
         self.timeout = timeout
         self.connect_timeout = connect_timeout
+        self.max_concurrency = max_concurrency
         self.semaphore = asyncio.Semaphore(max_concurrency)
 
+        # 共享 HTTP/HTTPS ClientSession
+        self._http_connector = aiohttp.TCPConnector(
+            ssl=False,
+            limit=max_concurrency,
+            limit_per_host=max_concurrency,
+            force_close=False,
+        )
+        self._timeout = aiohttp.ClientTimeout(
+            total=timeout, connect=connect_timeout
+        )
+        self._http_session = aiohttp.ClientSession(
+            connector=self._http_connector,
+            timeout=self._timeout,
+        )
+
     def _get_test_url(self, protocol: str) -> str:
         """获取测试 URL"""
         urls = self.TEST_URLS.get(protocol.lower(), self.TEST_URLS["http"])
@@ -53,20 +69,14 @@ class ValidatorService:
     async def _validate_http(self, ip: str, port: int, protocol: str, start: float) -> Tuple[bool, float]:
         """验证 HTTP/HTTPS 代理"""
         proxy_url = f"http://{ip}:{port}"
-        connector = aiohttp.TCPConnector(ssl=False, limit=0, force_close=True)
-        timeout = aiohttp.ClientTimeout(total=self.timeout, connect=self.connect_timeout)
         test_url = self._get_test_url(protocol)
 
-        try:
-            async with aiohttp.ClientSession(connector=connector, timeout=timeout) as session:
-                async with session.get(test_url, proxy=proxy_url, allow_redirects=True) as response:
-                    if response.status in (200, 301, 302):
-                        latency = round((time.time() - start) * 1000, 2)
-                        logger.info(f"HTTP valid: {ip}:{port} ({protocol}) {latency}ms")
-                        return True, latency
-                    return False, 0.0
-        finally:
-            await connector.close()
+        async with self._http_session.get(test_url, proxy=proxy_url, allow_redirects=True) as response:
+            if response.status in (200, 301, 302):
+                latency = round((time.time() - start) * 1000, 2)
+                logger.info(f"HTTP valid: {ip}:{port} ({protocol}) {latency}ms")
+                return True, latency
+            return False, 0.0
 
     async def _validate_socks(self, ip: str, port: int, protocol: str, start: float) -> Tuple[bool, float]:
         """验证 SOCKS4/SOCKS5 代理"""
@@ -95,3 +105,7 @@ class ValidatorService:
                     return False, 0.0
         finally:
             await connector.close()
+
+    async def close(self):
+        """关闭共享的 HTTP ClientSession"""
+        await self._http_session.close()