feat: 新增「部署客户端」日志采集器模块

三种采集器（host-promtail / k8s-daemonset / k8s-fluentbit-sidecar），每种关联已部署 Loki：
- host-promtail：SSH 安装 Promtail（复用 deployBinary）
- k8s-daemonset：helm 安装 Promtail DaemonSet（复用 deployHelm）
- k8s-fluentbit-sidecar：kubectl patch 注入 Fluent Bit sidecar

含 Collector 数据模型、三个部署器、配置模板、CRUD API、前端页面。
附带 UI 优化：ErrorBoundary、部署卡片浏览器访问按钮、菜单名称调整。

Co-Authored-By: Claude <noreply@anthropic.com>

backend/routers/router.go

@@ -28,6 +28,7 @@ func SetupRouter() *gin.Engine {
 	hostCtrl := controllers.NewHostController()
 	storageCtrl := controllers.NewStorageController()
 	deploymentCtrl := controllers.NewDeploymentController()
+	collectorCtrl := controllers.NewCollectorController()
 
 	// API v1
 	api := r.Group("/api/v1")
@@ -83,6 +84,15 @@ func SetupRouter() *gin.Engine {
 	authorized.GET("/deployments/:id/logs", deploymentCtrl.GetLogs)
 	authorized.GET("/deployments/stats", deploymentCtrl.GetStats)
 
+	// Collectors（日志采集器 / 部署客户端）
+	authorized.GET("/collectors", collectorCtrl.List)
+	authorized.GET("/collectors/:id", collectorCtrl.Get)
+	authorized.POST("/collectors", collectorCtrl.Create)
+	authorized.PUT("/collectors/:id", collectorCtrl.Update)
+	authorized.DELETE("/collectors/:id", collectorCtrl.Delete)
+	authorized.POST("/collectors/:id/install", collectorCtrl.Install)
+	authorized.POST("/collectors/:id/uninstall", collectorCtrl.Uninstall)
+
 	// Static files - use executable directory as base
 	distPath := findDistPath()