refactor: 全面重构核心架构，消除反复修改的根因

- 删除 ValidationQueue 双轨持久化队列，替换为纯内存 AsyncWorkerPool
- 引入统一后台任务框架 JobExecutor（Job/CrawlJob/ValidateAllJob）
- 新增 PluginRunner 统一插件执行（超时、重试、健康检查、统计）
- 重构 SchedulerService 职责收敛为仅定时触发 ValidateAllJob
- 使用 AsyncExitStack 重构 lifespan，安全管理长生命周期资源
- 路由层瘦身 50%+，业务异常上抛由全局中间件统一处理
- 实现设置全热更新（WorkerPool 并发、Validator 超时即时生效）
- 前端 Store 强制写后重新拉取，消除乐观更新数据不同步
- 删除 queue.py / task_repo.py / task_service.py
- 新增 execution 单元测试，全部 85 个测试通过

app/api/deps.py

@@ -3,10 +3,8 @@ from fastapi import Request
 from app.services.proxy_service import ProxyService
 from app.services.plugin_service import PluginService
 from app.services.scheduler_service import SchedulerService
-from app.services.validator_service import ValidatorService
-from app.repositories.proxy_repo import ProxyRepository
-from app.core.tasks.queue import ValidationQueue
-from app.core.config import settings as app_settings
+from app.services.plugin_runner import PluginRunner
+from app.core.execution import JobExecutor, AsyncWorkerPool
 
 
 def get_proxy_service() -> ProxyService:
@@ -18,36 +16,16 @@ def get_plugin_service() -> PluginService:
 
 
 def get_scheduler_service(request: Request) -> SchedulerService:
-    return request.app.state.scheduler_service
+    return request.app.state.scheduler
 
 
-def get_validation_queue(request: Request) -> ValidationQueue:
-    return request.app.state.validation_queue
+def get_executor(request: Request) -> JobExecutor:
+    return request.app.state.executor
 
 
-def create_scheduler_service(db_settings: dict | None = None) -> SchedulerService:
-    """在应用启动时创建 SchedulerService（非请求上下文）
-    
-    db_settings 来自数据库持久化设置，用于覆盖 .env / 默认值。
-    """
-    db_settings = db_settings or {}
-    validator = ValidatorService(
-        timeout=db_settings.get("validation_timeout", app_settings.validator_timeout),
-        connect_timeout=db_settings.get("connect_timeout", app_settings.validator_connect_timeout),
-        max_concurrency=db_settings.get("default_concurrency", app_settings.validator_max_concurrency),
-    )
-    proxy_repo = ProxyRepository()
-    queue = ValidationQueue(
-        validator=validator,
-        proxy_repo=proxy_repo,
-        worker_count=db_settings.get("default_concurrency", app_settings.validator_max_concurrency),
-        score_valid=app_settings.score_valid,
-        score_invalid=app_settings.score_invalid,
-        score_min=app_settings.score_min,
-        score_max=app_settings.score_max,
-    )
-    svc = SchedulerService(validation_queue=queue, proxy_repo=proxy_repo)
-    svc.interval_minutes = db_settings.get(
-        "validate_interval_minutes", 30
-    )
-    return svc
+def get_plugin_runner(request: Request) -> PluginRunner:
+    return request.app.state.plugin_runner
+
+
+def get_worker_pool(request: Request) -> AsyncWorkerPool:
+    return request.app.state.worker_pool