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

src/messages/en.json

@@ -74,9 +74,6 @@
   "navigation": {
     "home": "Home",
     "projects": "Projects",
-    "keywordCloud": "AI Word Cloud",
-    "timeline": "AI Timeline",
-    "blog": "Blog",
     "about": "About",
     "submitProject": "SUBMIT PROJECT"
   },
@@ -96,31 +93,5 @@
     "followUs": "Follow Us",
     "copyright": "© 2025 Agent Park. All rights reserved.",
     "designedFor": "DESIGNED FOR AI BUILDERS"
-  },
-  "keywordCloud": {
-    "metaTitle": "AI Hotspot Word Cloud - Agent Park",
-    "metaDescription": "Explore the evolution of quarterly AI hotspots, from Large Language Models to Agent Workflows",
-    "badge": "AI Trend Tracker",
-    "title": "Quarterly AI",
-    "titleHighlight": "Hotspot Word Cloud",
-    "subtitle": "From “Large Language Models” to “Agent Workflows”. Explore the evolution of AI discourse.",
-    "loading": "Loading...",
-    "loadFailed": "Failed to load",
-    "retry": "Retry",
-    "hotKeyword": "“{word}” is the hottest keyword this quarter!"
-  },
-  "timeline": {
-    "metaTitle": "AI Timeline - Agent Park",
-    "metaDescription": "Explore the evolution of AI large language models from 2017 Transformer to today",
-    "title": "THE STORY OF A.I.",
-    "subtitle": "Pinned. Stacked. Zigzagged.",
-    "emptyData": "No data available",
-    "collecting": "Timeline data is being collected...",
-    "joinThePark": "Join the Park",
-    "subscribeDesc": "Subscribe to the Agent Park weekly zine. No spam, just ducks and data.",
-    "emailPlaceholder": "Your email here...",
-    "subscribe": "SUBSCRIBE",
-    "agreeToBeCool": "I agree to be cool.",
-    "earlier": "Earlier"
   }
 }