全面架构重构：建立分层架构与高度可扩展的插件系统

后端重构：
- 新增分层架构：API Routes -> Services -> Repositories -> Infrastructure
- 彻底移除全局单例，全面采用 FastAPI 依赖注入
- 新增 api/ 目录拆分路由（proxies, plugins, scheduler, settings, stats）
- 新增 services/ 业务逻辑层：ProxyService, PluginService, SchedulerService, ValidatorService, SettingsService
- 新增 repositories/ 数据访问层：ProxyRepository, SettingsRepository, PluginSettingsRepository
- 新增 models/ 层：Pydantic Schemas + Domain Models
- 重写 core/config.py：采用 Pydantic Settings 管理配置
- 新增 core/db.py：基于 asynccontextmanager 的连接管理，支持数据库迁移
- 新增 core/exceptions.py：统一业务异常体系

插件系统重构（核心）：
- 新增 core/plugin_system/：BaseCrawlerPlugin + PluginRegistry
- 采用显式注册模式（装饰器 + plugins/__init__.py），类型安全、测试友好
- 新增 plugins/base.py：BaseHTTPPlugin 通用 HTTP 爬虫基类
- 迁移全部 7 个插件到新架构（fate0, proxylist_download, ip3366, ip89, kuaidaili, speedx, yundaili）
- 插件状态持久化到 plugin_settings 表

任务调度重构：
- 新增 core/tasks/queue.py：ValidationQueue + WorkerPool
- 解耦爬取与验证：爬虫只负责爬取，代理提交队列后由 Worker 异步验证
- 调度器定时从数据库拉取存量代理并分批投入验证队列

前端调整：
- 新增 frontend/src/services/ 层拆分 API 调用逻辑
- 调整 stores/ 和 views/ 使用 Service 层
- 保持 API 兼容性，页面无需大幅修改

其他：
- 新增 main.py 作为新入口
- 新增 DESIGN.md 架构设计文档
- 更新 requirements.txt 增加 pydantic-settings

api/routes/plugins.py

@@ -0,0 +1,139 @@
+"""插件相关路由"""
+from fastapi import APIRouter, Depends
+from services.plugin_service import PluginService
+from services.scheduler_service import SchedulerService
+from models.schemas import PluginToggleRequest
+from api.deps import get_plugin_service, get_scheduler_service
+from core.log import logger
+
+router = APIRouter(prefix="/api/plugins", tags=["plugins"])
+
+
+def success_response(message: str, data=None):
+    return {"code": 200, "message": message, "data": data}
+
+
+def error_response(message: str, code: int = 500):
+    return {"code": code, "message": message, "data": None}
+
+
+@router.get("")
+async def list_plugins(service: PluginService = Depends(get_plugin_service)):
+    plugins = await service.list_plugins()
+    return success_response(
+        "获取插件列表成功",
+        {
+            "plugins": [
+                {
+                    "id": p.id,
+                    "name": p.display_name,  # 保持旧版本兼容：name 用于展示
+                    "display_name": p.display_name,
+                    "description": p.description,
+                    "enabled": p.enabled,
+                    "last_run": p.last_run.isoformat() if p.last_run else None,
+                    "success_count": p.success_count,
+                    "failure_count": p.failure_count,
+                }
+                for p in plugins
+            ]
+        },
+    )
+
+
+@router.put("/{plugin_id}/toggle")
+async def toggle_plugin(
+    plugin_id: str,
+    request: PluginToggleRequest,
+    service: PluginService = Depends(get_plugin_service),
+):
+    success = await service.toggle_plugin(plugin_id, request.enabled)
+    if not success:
+        return error_response("插件不存在", 404)
+    return success_response(
+        f"插件 {plugin_id} 已{'启用' if request.enabled else '禁用'}",
+        {"plugin_id": plugin_id, "enabled": request.enabled},
+    )
+
+
+@router.post("/{plugin_id}/crawl")
+async def crawl_plugin(
+    plugin_id: str,
+    plugin_service: PluginService = Depends(get_plugin_service),
+    scheduler_service: SchedulerService = Depends(get_scheduler_service),
+):
+    plugin = plugin_service.get_plugin(plugin_id)
+    if not plugin:
+        return error_response("插件不存在", 404)
+
+    try:
+        results = await plugin_service.run_plugin(plugin_id)
+        if not results:
+            return success_response(
+                f"插件 {plugin_id} 爬取完成，未获取到代理",
+                {"plugin_id": plugin_id, "proxy_count": 0, "valid_count": 0},
+            )
+
+        logger.info(f"Plugin {plugin_id} crawled {len(results)} proxies, sending to validation queue")
+        scheduler_service.validation_queue.reset_stats()
+        await scheduler_service.validation_queue.submit(results)
+        # 等待队列排空（最多等 30 秒，避免前端超时）
+        try:
+            await asyncio.wait_for(scheduler_service.validation_queue.drain(), timeout=30.0)
+        except asyncio.TimeoutError:
+            pass
+
+        valid_count = scheduler_service.validation_queue.valid_count
+        invalid_count = scheduler_service.validation_queue.invalid_count
+
+        return success_response(
+            f"插件 {plugin_id} 爬取并验证完成",
+            {
+                "plugin_id": plugin_id,
+                "proxy_count": len(results),
+                "valid_count": valid_count,
+                "invalid_count": invalid_count,
+            },
+        )
+    except Exception as e:
+        logger.error(f"Crawl plugin {plugin_id} failed: {e}")
+        return error_response(f"插件爬取失败: {str(e)}")
+
+
+@router.post("/crawl-all")
+async def crawl_all(
+    plugin_service: PluginService = Depends(get_plugin_service),
+    scheduler_service: SchedulerService = Depends(get_scheduler_service),
+):
+    try:
+        results = await plugin_service.run_all_plugins()
+        if not results:
+            return success_response(
+                "所有插件爬取完成，未获取到代理",
+                {"total_crawled": 0, "valid_count": 0, "invalid_count": 0},
+            )
+
+        logger.info(f"All plugins crawled {len(results)} unique proxies, sending to validation queue")
+        scheduler_service.validation_queue.reset_stats()
+        await scheduler_service.validation_queue.submit(results)
+        try:
+            await asyncio.wait_for(scheduler_service.validation_queue.drain(), timeout=60.0)
+        except asyncio.TimeoutError:
+            pass
+
+        valid_count = scheduler_service.validation_queue.valid_count
+        invalid_count = scheduler_service.validation_queue.invalid_count
+
+        return success_response(
+            "所有插件爬取并验证完成",
+            {
+                "total_crawled": len(results),
+                "valid_count": valid_count,
+                "invalid_count": invalid_count,
+            },
+        )
+    except Exception as e:
+        logger.error(f"Crawl all failed: {e}")
+        return error_response(f"批量爬取失败: {str(e)}")
+
+
+import asyncio