fix(pages): 修复 TypeScript 错误、硬编码字符串，移除死代码

- 修复 LiveClock.tsx CopyButton size 属性类型错误 (small → sm)
- 修复 ToolCard.tsx 紫色 RGB 值拼写错误 (147,51,2 purple → 147,51,232)
- 替换 4 处硬编码中文为 i18n 调用 (StorageCleaner, JsonTools)
- MarkdownToHtml 预览链接色改为 CSS 变量以支持暗黑模式
- 移除 Base64Converter 中已被 Base64ConverterSection 替代的死代码
  (FileMode.tsx, ImageMode.tsx 及其测试文件)
- 更新 README.md 移除对已删除文件的引用

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

i18n/locales/en/storageCleaner.json

@@ -2,6 +2,7 @@
   "pageTitle": "Storage Cleaner",
   "pageSubtitle": "Clear cache, cookies, and local storage",
   "loading": "Loading...",
+  "initializing": "Reading site data...",
   "occupied": "Occupied {{size}}",
   "cleaning": "Cleaning...",
   "cleanNow": "Clean Now",