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/components/LanguageSwitcher.tsx

@@ -1,5 +1,5 @@
 import { useState, useEffect } from "react";
-import { getLangFromUrl, getLocalizedPath, type Lang } from "@/i18n/utils";
+import { getLocalizedPath, type Lang } from "@/i18n/utils"; // getLangFromUrl is removed as Astro.currentLocale is used now.
 import { languages as i18nLanguages, defaultLang } from "@/i18n/ui";
 import { Languages, Check } from "lucide-react";
 import { motion, AnimatePresence } from "framer-motion";
@@ -30,12 +30,41 @@ export default function LanguageSwitcher({ lang: initialLang }: LanguageSwitcher
 
   const toggleOpen = () => setIsOpen(!isOpen);
 
-  const handleSelectLanguage = (lang: typeof availableLanguages[0]) => {
-    setSelectedLanguage(lang);
+  const handleSelectLanguage = (languageOpt: typeof availableLanguages[0]) => {
+    setSelectedLanguage(languageOpt);
     setIsOpen(false);
     if (typeof window !== 'undefined') {
-      const currentPath = window.location.pathname.replace(/\/en|\/zh/, ''); // Remove lang prefix
-      const newPath = getLocalizedPath(currentPath || '/', lang.code);
+      const currentPathname = window.location.pathname;
+      const currentPathParts = currentPathname.split('/').filter(p => p);
+      let basePath = '';
+
+      // Check if the first part of the path is a known language code
+      if (currentPathParts.length > 0 && Object.keys(i18nLanguages).includes(currentPathParts[0])) {
+        basePath = '/' + currentPathParts.slice(1).join('/');
+      } else {
+        basePath = currentPathname;
+      }
+      
+      // Ensure basePath always starts with a slash, or is just a slash for the root
+      if (!basePath.startsWith('/')) {
+        basePath = '/' + basePath;
+      }
+      if (basePath === '//') basePath = '/';
+
+      let newPath;
+      // If the target language is the default language and prefixDefaultLocale is false (as per our astro.config.mjs)
+      // then no language prefix is needed.
+      if (languageOpt.code === defaultLang) {
+        newPath = basePath;
+      } else {
+        // For non-default languages, prefix with the language code.
+        newPath = `/${languageOpt.code}${basePath}`;
+      }
+
+      // Clean up double slashes, just in case
+      newPath = newPath.replace(/\/\/+/g, '/');
+      if (newPath === '') newPath = '/'; // Handle case where basePath might be empty resulting in just /zh or /en
+
       window.location.href = newPath;
     }
   };

src/components/MotionWrapper.tsx

@@ -2,25 +2,11 @@ import React from "react";
 import { motion } from "framer-motion";
 import type { MotionProps } from "framer-motion";
 
-interface MotionWrapperProps extends MotionProps {
+interface MotionWrapperProps extends Omit<MotionProps, 'custom'> {
   children: React.ReactNode;
   delay?: number;
 }
 
-// Default animations for sections
-const defaultAnimations = {
-  hidden: { opacity: 0, y: 20 },
-  visible: (delay: number = 0) => ({
-    opacity: 1,
-    y: 0,
-    transition: {
-      duration: 0.6,
-      delay: delay,
-      ease: "easeOut",
-    },
-  }),
-};
-
 export default function MotionWrapper({
   children,
   delay = 0,
@@ -31,7 +17,18 @@ export default function MotionWrapper({
       initial="hidden"
       whileInView="visible"
       viewport={{ once: true, margin: "-100px" }}
-      variants={defaultAnimations}
+      variants={{
+        hidden: { opacity: 0, y: 20 },
+        visible: {
+          opacity: 1,
+          y: 0,
+          transition: {
+            duration: 0.6,
+            delay,
+            ease: [0.43, 0.13, 0.23, 0.96]
+          }
+        }
+      }}
       custom={delay}
       {...props}
     >