refactor: 移除 AI 词云、AI 时间轴和博客模块

暂停开发以下功能，将设计文档移至未完成计划文件夹：

- AI 词云 (Keyword Cloud): 前端、API、数据库模型、n8n 工作流
- AI 时间轴 (AI Timeline): 前端、API、数据库模型
- 博客 (Blog): 导航链接占位

变更内容：
- 删除词云和时间轴的前端页面及组件
- 删除 /api/keyword-cloud/* 和 /api/events/* API 端点
- 从 prisma/schema.prisma 移除 Keyword, Quarter, VisualStyleRule, KeywordCloudErrorLog, AIEvent 模型
- 从 validations.ts 移除相关 Zod Schema
- 从国际化消息中移除 keywordCloud/timeline 命名空间
- 从导航菜单移除词云、时间轴、博客链接
- 更新 CLAUDE.md 移除词云系统文档

设计文档已移至 .omc/plans/postponed-features/ 供后续恢复开发参考

prisma/schema.prisma

@@ -24,40 +24,6 @@ model ExternalLink {
   @@map("external_links")
 }
 
-model KeywordCloudErrorLog {
-  id           Int      @id @default(autoincrement())
-  quarter      String
-  keyword      String?
-  errorType    String
-  errorMessage String
-  rawData      Json?
-  createdAt    DateTime @default(now())
-
-  @@index([errorType], map: "idx_keywordCloudErrorLog_errorType")
-  @@index([quarter], map: "idx_keywordCloudErrorLog_quarter")
-  @@map("keyword_cloud_error_logs")
-}
-
-model Keyword {
-  id             Int      @id @default(autoincrement())
-  word           String
-  trendScore     Int
-  quarterId      Int
-  description    String
-  descriptionEn  String?
-  detailPoints   Json
-  detailPointsEn Json?
-  visualConfig   Json
-  createdAt      DateTime @default(now())
-  updatedAt      DateTime @updatedAt
-  quarter        Quarter  @relation(fields: [quarterId], references: [id], onDelete: Cascade)
-
-  @@index([quarterId], map: "idx_keyword_quarterId")
-  @@index([trendScore], map: "idx_keyword_trendScore")
-  @@index([word], map: "idx_keyword_word")
-  @@map("keywords")
-}
-
 model ProjectDiscoveryTask {
   id                 String     @id @default(cuid())
   status             TaskStatus @default(PENDING)
@@ -117,24 +83,6 @@ model Project {
   @@map("projects")
 }
 
-model Quarter {
-  id           Int        @id @default(autoincrement())
-  quarter      String     @unique
-  title        String
-  titleEn      String?
-  subtitle     String?
-  subtitleEn   String?
-  displayOrder Int        @default(0)
-  isActive     Boolean    @default(true)
-  createdAt    DateTime   @default(now())
-  updatedAt    DateTime   @updatedAt
-  keywords     Keyword[]
-
-  @@index([displayOrder], map: "idx_quarter_displayOrder")
-  @@index([quarter], map: "idx_quarter_quarter")
-  @@map("quarters")
-}
-
 model Tag {
   id           String         @id @default(cuid())
   name         String         @unique
@@ -147,25 +95,6 @@ model Tag {
   @@map("tags")
 }
 
-model VisualStyleRule {
-  id        Int      @id @default(autoincrement())
-  name      String   @unique
-  minScore  Int
-  maxScore  Int
-  color     String
-  size      String
-  border    String
-  rotation  String?
-  priority  Int      @default(0)
-  enabled   Boolean  @default(true)
-  createdAt DateTime @default(now())
-  updatedAt DateTime @updatedAt
-
-  @@index([enabled], map: "idx_visualStyleRule_enabled")
-  @@index([minScore, maxScore], map: "idx_visualStyleRule_scoreRange")
-  @@map("visual_style_rules")
-}
-
 enum LinkType {
   WEBSITE
   GITHUB
@@ -185,24 +114,3 @@ enum TaskStatus {
   FAILED
 }
 
-// ================================
-// AI Timeline System Models
-// ================================
-
-model AIEvent {
-  id            String   @id @default(cuid())
-  title         String
-  titleEn       String?
-  eventDate     DateTime
-  description   String
-  descriptionEn String?
-  imageUrl      String
-  sourceUrl     String?
-
-  createdAt     DateTime @default(now())
-  updatedAt     DateTime @updatedAt
-
-  @@index([eventDate(sort: Desc)])
-  @@index([createdAt])
-  @@map("ai_events")
-}