feat(config): add sensitive word filtering system with database support

Implement sensitive word filtering feature with configurable database and Redis
support. Add security enhancements including WebSocket origin validation, improved
password strength requirements, timing attack prevention, and production JWT secret
validation. Add batch operation validation limits and optimize user blocking
queries with subqueries.

BREAKING CHANGE: Password validation now requires minimum 8 characters with uppercase,
lowercase, and digit (was 6-50 characters without complexity requirements)

internal/dto/dto.go

@@ -972,12 +972,12 @@ type AdminModeratePostRequest struct {
 
 // AdminBatchDeletePostsRequest 批量删除帖子请求
 type AdminBatchDeletePostsRequest struct {
-	IDs []string `json:"ids" binding:"required,min=1"`
+	IDs []string `json:"ids" binding:"required,min=1,max=100,dive,required"`
 }
 
 // AdminBatchModeratePostsRequest 批量审核帖子请求
 type AdminBatchModeratePostsRequest struct {
-	IDs    []string `json:"ids" binding:"required,min=1"`
+	IDs    []string `json:"ids" binding:"required,min=1,max=100,dive,required"`
 	Status string   `json:"status" binding:"required,oneof=published rejected"`
 }
 
@@ -1045,7 +1045,7 @@ type AdminCommentDetailResponse struct {
 
 // AdminBatchDeleteCommentsRequest 批量删除评论请求
 type AdminBatchDeleteCommentsRequest struct {
-	IDs []string `json:"ids" binding:"required,min=1"`
+	IDs []string `json:"ids" binding:"required,min=1,max=100,dive,required"`
 }
 
 // ==================== Admin Group DTOs ====================