feat(i18n): implement astro i18n integration and refactor locale handling

- Add i18n configuration to astro.config.mjs with default locale and routing
- Refactor language handling to use Astro.currentLocale instead of URL parsing
- Update tsconfig to include only necessary files for better type checking
- Improve LanguageSwitcher to handle routing based on astro i18n config
- Add new translation keys and update components to use dynamic titles
- Simplify MotionWrapper component by removing unused default animations

src/i18n/utils.ts

@@ -4,11 +4,7 @@ import { ui, defaultLang, languages } from './ui';
 export type Lang = keyof typeof languages;
 export type UiKeys = keyof typeof ui[typeof defaultLang];
 
-export function getLangFromUrl(url: URL): Lang {
-  const [, lang] = url.pathname.split('/');
-  if (lang in languages) return lang as Lang;
-  return defaultLang;
-}
+
 
 export function useTranslations(lang: Lang | undefined) {
   const currentLang = lang || defaultLang;
@@ -27,15 +23,30 @@ export function getLocalizedPath(path: string, lang: Lang | undefined): string {
   const currentLang = lang || defaultLang;
   const basePath = import.meta.env.BASE_URL === '/' ? '' : import.meta.env.BASE_URL;
 
-  // If the current language is the default language, do not add a language prefix.
-  if (currentLang === defaultLang) {
-    const fullPath = `${basePath}${path.startsWith('/') ? path : `/${path}`}`;
-    return fullPath.replace(/\/\/+/g, '/');
+  // Astro's i18n routing handles prefixing automatically based on astro.config.mjs settings.
+  // We just need to ensure the path is correctly formed relative to the base.
+  // If a language is explicitly provided and it's not the default, 
+  // and prefixDefaultLocale is false (meaning default lang has no prefix),
+  // we might need to add it. However, Astro typically handles this.
+  // For now, let's assume Astro's routing takes care of the prefix.
+  // This function might become simpler or even unnecessary depending on how LanguageSwitcher is used.
+
+  let newPath = path;
+  // Ensure path starts with a slash if it's not an external URL
+  if (!newPath.startsWith('/') && !newPath.match(/^https?:\/\//)) {
+    newPath = `/${newPath}`;
   }
 
-  // Otherwise, add the language prefix.
-  const langPrefix = `/${currentLang}`;
-  const fullPath = `${basePath}${langPrefix}${path.startsWith('/') ? path : `/${path}`}`;
-  // Remove any double slashes that might occur.
-  return fullPath.replace(/\/\/+/g, '/');
+  // If prefixDefaultLocale is false (default in our config) and currentLang is not defaultLang,
+  // Astro will expect /zh/path. If currentLang is defaultLang, it expects /path.
+  // If prefixDefaultLocale is true, all locales get a prefix: /en/path, /zh/path.
+
+  // Given our astro.config.mjs: prefixDefaultLocale: false
+  // If lang is 'zh', the path should be /zh/your-path
+  // If lang is 'en' (default), the path should be /your-path
+  // Astro's <a href> or Astro.redirect should handle this correctly when given a root-relative path.
+  // This function's main job is to ensure the base path and the target path are combined correctly.
+
+  const fullPath = `${basePath}${newPath}`;
+  return fullPath.replace(/\/\/+/g, '/'); // Clean up any double slashes
 }