feat(handler): 实现运维监控 API 处理器和中间件

- 新增 ops 错误日志记录器（ops_error_logger.go）
- 新增 ops 主处理器（ops_handler.go）
- 新增告警管理处理器（ops_alerts_handler.go）
- 新增仪表板处理器（ops_dashboard_handler.go）
- 新增实时监控处理器（ops_realtime_handler.go）
- 新增配置管理处理器（ops_settings_handler.go）
- 新增 WebSocket 处理器（ops_ws_handler.go）
- 扩展设置 DTO 支持 ops 配置
- 新增客户端请求 ID 中间件（client_request_id.go）
- 新增 WebSocket 查询令牌认证中间件（ws_query_token_auth.go）
- 更新管理员认证中间件支持 ops 路由
- 注册 handler 依赖注入

backend/internal/handler/admin/ops_settings_handler.go

@@ -0,0 +1,103 @@
+package admin
+
+import (
+	"net/http"
+
+	"github.com/Wei-Shaw/sub2api/internal/pkg/response"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/gin-gonic/gin"
+)
+
+// GetEmailNotificationConfig returns Ops email notification config (DB-backed).
+// GET /api/v1/admin/ops/email-notification/config
+func (h *OpsHandler) GetEmailNotificationConfig(c *gin.Context) {
+	if h.opsService == nil {
+		response.Error(c, http.StatusServiceUnavailable, "Ops service not available")
+		return
+	}
+	if err := h.opsService.RequireMonitoringEnabled(c.Request.Context()); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	cfg, err := h.opsService.GetEmailNotificationConfig(c.Request.Context())
+	if err != nil {
+		response.Error(c, http.StatusInternalServerError, "Failed to get email notification config")
+		return
+	}
+	response.Success(c, cfg)
+}
+
+// UpdateEmailNotificationConfig updates Ops email notification config (DB-backed).
+// PUT /api/v1/admin/ops/email-notification/config
+func (h *OpsHandler) UpdateEmailNotificationConfig(c *gin.Context) {
+	if h.opsService == nil {
+		response.Error(c, http.StatusServiceUnavailable, "Ops service not available")
+		return
+	}
+	if err := h.opsService.RequireMonitoringEnabled(c.Request.Context()); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	var req service.OpsEmailNotificationConfigUpdateRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request body")
+		return
+	}
+
+	updated, err := h.opsService.UpdateEmailNotificationConfig(c.Request.Context(), &req)
+	if err != nil {
+		// Most failures here are validation errors from request payload; treat as 400.
+		response.Error(c, http.StatusBadRequest, err.Error())
+		return
+	}
+	response.Success(c, updated)
+}
+
+// GetAlertRuntimeSettings returns Ops alert evaluator runtime settings (DB-backed).
+// GET /api/v1/admin/ops/runtime/alert
+func (h *OpsHandler) GetAlertRuntimeSettings(c *gin.Context) {
+	if h.opsService == nil {
+		response.Error(c, http.StatusServiceUnavailable, "Ops service not available")
+		return
+	}
+	if err := h.opsService.RequireMonitoringEnabled(c.Request.Context()); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	cfg, err := h.opsService.GetOpsAlertRuntimeSettings(c.Request.Context())
+	if err != nil {
+		response.Error(c, http.StatusInternalServerError, "Failed to get alert runtime settings")
+		return
+	}
+	response.Success(c, cfg)
+}
+
+// UpdateAlertRuntimeSettings updates Ops alert evaluator runtime settings (DB-backed).
+// PUT /api/v1/admin/ops/runtime/alert
+func (h *OpsHandler) UpdateAlertRuntimeSettings(c *gin.Context) {
+	if h.opsService == nil {
+		response.Error(c, http.StatusServiceUnavailable, "Ops service not available")
+		return
+	}
+	if err := h.opsService.RequireMonitoringEnabled(c.Request.Context()); err != nil {
+		response.ErrorFrom(c, err)
+		return
+	}
+
+	var req service.OpsAlertRuntimeSettings
+	if err := c.ShouldBindJSON(&req); err != nil {
+		response.BadRequest(c, "Invalid request body")
+		return
+	}
+
+	updated, err := h.opsService.UpdateOpsAlertRuntimeSettings(c.Request.Context(), &req)
+	if err != nil {
+		response.Error(c, http.StatusBadRequest, err.Error())
+		return
+	}
+	response.Success(c, updated)
+}
+