refactor(types): centralize type definitions in shared types file

Move all interface and type definitions to src/types/index.ts to reduce code duplication and improve maintainability. This includes types for components, blog posts, personal info, and localization.

src/components/layout/BlogNavigation.astro

@@ -1,4 +1,6 @@
 ---
+import { type BlogPost as BaseBlogPost } from '@/types';
+
 const currentPath = Astro.url.pathname;
 const isZh = currentPath.includes('/zh/');
 const lang = isZh ? 'zh' : 'en';

src/components/layout/TableOfContents.astro

@@ -1,5 +1,5 @@
 ---
-import type { Lang } from '../../i18n/utils';
+import { type Lang } from '@/types';
 
 interface Props {
   lang: Lang;