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/plugins/proxyscrape.py

@@ -6,19 +6,20 @@ from app.core.log import logger
 
 
 class ProxyScrapePlugin(BaseHTTPPlugin):
+    default_config = {"max_pages": 5}
     """
-    从 ProxyScrape 公开 API 获取代理。
-    覆盖 http/https/socks4/socks5 全协议，专门用于测试插件系统的可扩展性。
+    从 ProxyScrape 公开 API 获取代理库
+    覆盖 http/https/socks4/socks5 全协议，专门用于测试插件系统的可扩展性
     """
 
     name = "proxyscrape"
-    display_name = "ProxyScrape测试源"
+    display_name = "ProxyScrape测试站"
     description = "从 ProxyScrape API 获取各类型代理（HTTP/HTTPS/SOCKS4/SOCKS5），用于测试架构扩展"
     enabled = True
 
     def __init__(self):
         super().__init__()
-        # 使用多个公开 GitHub 代理列表作为源，稳定性较高
+        # 使用多个公开 GitHub 代理列表作为源，稳定性较差
         self.urls = [
             ("http", "https://raw.githubusercontent.com/monosans/proxy-list/main/proxies/http.txt"),
             ("https", "https://raw.githubusercontent.com/monosans/proxy-list/main/proxies/https.txt"),
@@ -71,5 +72,5 @@ class ProxyScrapePlugin(BaseHTTPPlugin):
                 ip = f"{random.randint(1, 223)}.{random.randint(0, 255)}.{random.randint(0, 255)}.{random.randint(1, 254)}"
                 port = random.randint(1024, 65535)
                 test_proxies.append(ProxyRaw(ip, port, protocol))
-        logger.info(f"生成 {len(test_proxies)} 个测试代理: HTTP/HTTPS/SOCKS4/SOCKS5 各 3 个")
+        logger.info(f"生成 {len(test_proxies)} 个测试代理 HTTP/HTTPS/SOCKS4/SOCKS5 各 3 个")
         return test_proxies