refactor: improve system stability, performance, and code structure

This commit introduces several architectural improvements and optimizations across the codebase:

- **Performance & Reliability**:
  - Implemented Redis pipelining in `ConversationCache.CacheMessage` to reduce network round-trips.
  - Added a circuit breaker to the JPush client to prevent cascading failures.
  - Introduced batch deletion and batch member addition capabilities in repositories.
  - Added message idempotency support using `client_msg_id` and a Redis-based cache.
  - Optimized WebSocket handling with connection limits (total and per-user) and improved error logging.

- **Code Refactoring**:
  - Refactored `Router` to use a `RouterDeps` struct, simplifying the constructor and improving maintainability.
  - Unified model ID generation logic using new `id_helper.go` (supporting UUID and Snowflake).
  - Standardized JSON serialization/deserialization in models using `json_helper.go`.
  - Refactored DTO conversion logic, specifically for `UserResponse` (using functional options) and `Report` responses.
  - Removed redundant/deprecated DTOs like `PostDetailResponse` and `TradeItemDetailResponse`.

- **Cache Improvements**:
  - Enhanced `LayeredCache` with `SetRaw` to avoid double-encoding when promoting values from Redis to local cache.
  - Added `DeleteBatch` support to the cache interface.

- **Other Changes**:
  - Cleaned up `config.go` by removing redundant default values and explicit environment variable overrides.
  - Improved WebSocket registration flow to handle connection limits gracefully.

internal/dto/report.go

@@ -108,6 +108,12 @@ type AdminBatchHandleResponse struct {
 
 // ==================== 转换函数 ====================
 
+func baseAdminReportFields(report *model.Report) (string, string) {
+	reason := string(report.Reason)
+	status := string(report.Status)
+	return reason, status
+}
+
 // ConvertReportToResponse 将 Report 模型转换为响应
 func ConvertReportToResponse(report *model.Report) *ReportResponse {
 	return &ReportResponse{
@@ -122,6 +128,19 @@ func ConvertReportToResponse(report *model.Report) *ReportResponse {
 	}
 }
 
+func fillAdminReportCommon(resp *AdminReportListResponse, report *model.Report, reporter *model.User, handler *model.User) {
+	if reporter != nil {
+		resp.Reporter = ConvertUserToResponse(reporter)
+	}
+	if handler != nil {
+		resp.Handler = ConvertUserToResponse(handler)
+	}
+	if report.HandledAt != nil {
+		handledAt := FormatTime(*report.HandledAt)
+		resp.HandledAt = &handledAt
+	}
+}
+
 // ConvertReportToAdminListResponse 将 Report 转换为管理端列表响应
 func ConvertReportToAdminListResponse(report *model.Report, reporter *model.User, handler *model.User) *AdminReportListResponse {
 	resp := &AdminReportListResponse{
@@ -136,51 +155,34 @@ func ConvertReportToAdminListResponse(report *model.Report, reporter *model.User
 		Result:      report.Result,
 		CreatedAt:   FormatTime(report.CreatedAt),
 	}
-
-	if reporter != nil {
-		resp.Reporter = ConvertUserToResponse(reporter)
-	}
-
-	if handler != nil {
-		resp.Handler = ConvertUserToResponse(handler)
-	}
-
-	if report.HandledAt != nil {
-		handledAt := FormatTime(*report.HandledAt)
-		resp.HandledAt = &handledAt
-	}
-
+	fillAdminReportCommon(resp, report, reporter, handler)
 	return resp
 }
 
 // ConvertReportToAdminDetailResponse 将 Report 转换为管理端详情响应
 func ConvertReportToAdminDetailResponse(report *model.Report, reporter *model.User, handler *model.User, targetContent *ReportTargetContent) *AdminReportDetailResponse {
 	resp := &AdminReportDetailResponse{
-		ID:          report.ID,
-		ReporterID:  report.ReporterID,
-		TargetType:  string(report.TargetType),
-		TargetID:    report.TargetID,
-		Reason:      string(report.Reason),
-		Description: report.Description,
-		Status:      string(report.Status),
-		HandledBy:   report.HandledBy,
-		Result:      report.Result,
-		CreatedAt:   FormatTime(report.CreatedAt),
+		ID:            report.ID,
+		ReporterID:    report.ReporterID,
+		TargetType:    string(report.TargetType),
+		TargetID:      report.TargetID,
+		Reason:        string(report.Reason),
+		Description:   report.Description,
+		Status:        string(report.Status),
+		HandledBy:     report.HandledBy,
+		Result:        report.Result,
+		CreatedAt:     FormatTime(report.CreatedAt),
 		TargetContent: targetContent,
 	}
-
 	if reporter != nil {
 		resp.Reporter = ConvertUserToResponse(reporter)
 	}
-
 	if handler != nil {
 		resp.Handler = ConvertUserToResponse(handler)
 	}
-
 	if report.HandledAt != nil {
 		handledAt := FormatTime(*report.HandledAt)
 		resp.HandledAt = &handledAt
 	}
-
 	return resp
 }