fix: 全面修复代码问题并优化架构

修复问题：
- 添加缺失的 httpx 依赖到 requirements.txt
- 修复前端批量删除参数格式与后端不匹配（数组->对象数组）
- 移除 app/api/main.py 中重复创建 app 的冗余代码
- 修复 Plugins.vue v-model 直接修改 store 状态的 Vue 警告
- 修复 README 端口/启动命令文档与实际配置不一致
- 修正 pytest.ini 过时配置 (asyncio_default_fixture_loop_scope)
- 修复 WebUI index.html 语言设置为 zh-CN
- 修复 .gitignore 错误忽略 tests/ 目录

后端优化：
- 修复调度器默认间隔从 5 秒改为 30 分钟，避免无节制验证
- 修复 validate_all_now 在调度器停止时无法执行的 bug
- 设置保存后热更新运行中调度器的验证间隔
- 将 update_score 优化为原子单事务 SQL，消除并发竞态
- 导出功能改为真正的流式分批读取（iter_batches），降低大导出内存占用
- ProxyResponse Schema 补齐 response_time_ms 字段
- 日志级别改为从配置动态读取，不再硬编码 INFO
- 清理 validator_service 中的冗余 try/finally 代码

插件健壮性：
- 修复 ip3366/ip89/kuaidaili/proxylist_download/speedx/yundaili/proxyscrape
  的端口范围检查和 IPv6 地址解析问题（改用 rsplit + 1-65535 校验）
- 修复 PluginService.list_plugins 并发竞争条件
- 修复 run_all_plugins 去重逻辑与数据库 UNIQUE 约束保持一致
- 修复 proxyscrape 异常时错误跳过 fallback 的 bug

测试：
- 新增 7 个插件解析单元测试
- 新增 update_score 自动删除和 iter_batches 流式读取测试
- 全部 74 个测试通过

app/repositories/proxy_repo.py

@@ -76,23 +76,23 @@ class ProxyRepository:
         max_score: int = 100,
     ) -> bool:
         try:
-            async with db.execute(
-                "SELECT score FROM proxies WHERE ip = ? AND port = ?", (ip, port)
-            ) as cursor:
-                row = await cursor.fetchone()
-                if not row:
-                    return False
-                current_score = row[0]
-                new_score = max(min_score, min(max_score, current_score + delta))
-                await db.execute(
-                    "UPDATE proxies SET score = ?, last_check = CURRENT_TIMESTAMP WHERE ip = ? AND port = ?",
-                    (new_score, ip, port),
-                )
-                if new_score <= 0:
-                    # 只删除当前代理，避免误删其他无效代理
-                    await db.execute("DELETE FROM proxies WHERE ip = ? AND port = ?", (ip, port))
-                await db.commit()
-                return True
+            # 原子更新：计算新分数并直接更新
+            await db.execute(
+                """
+                UPDATE proxies
+                SET score = MAX(?, MIN(?, score + ?)),
+                    last_check = CURRENT_TIMESTAMP
+                WHERE ip = ? AND port = ?
+                """,
+                (min_score, max_score, delta, ip, port),
+            )
+            # 删除分数已降至 0 及以下的代理
+            await db.execute(
+                "DELETE FROM proxies WHERE ip = ? AND port = ? AND score <= ?",
+                (ip, port, min_score),
+            )
+            await db.commit()
+            return db.total_changes > 0
         except Exception as e:
             logger.error(f"update_score failed: {e}", exc_info=True)
             return False
@@ -156,19 +156,35 @@ class ProxyRepository:
         db: aiosqlite.Connection,
         protocol: Optional[str] = None,
         limit: int = 100000,
+        offset: int = 0,
     ) -> List[Proxy]:
         query = "SELECT ip, port, protocol, score, response_time_ms, last_check, created_at FROM proxies"
         params: List = []
         if protocol:
             query += " WHERE protocol = ?"
             params.append(protocol.lower())
-        query += " LIMIT ?"
-        params.append(limit)
+        query += " LIMIT ? OFFSET ?"
+        params.extend([limit, offset])
 
         async with db.execute(query, params) as cursor:
             rows = await cursor.fetchall()
             return [_row_to_proxy(row) for row in rows]
 
+    @staticmethod
+    async def iter_batches(
+        db: aiosqlite.Connection,
+        protocol: Optional[str] = None,
+        batch_size: int = 1000,
+    ):
+        """流式分批读取代理，避免一次性加载大量数据到内存"""
+        offset = 0
+        while True:
+            batch = await ProxyRepository.list_all(db, protocol, batch_size, offset)
+            if not batch:
+                break
+            yield batch
+            offset += batch_size
+
     @staticmethod
     async def list_paginated(
         db: aiosqlite.Connection,