feat(i18n): add internationalization support

This commit introduces internationalization (i18n) support by integrating the `@nuxtjs/i18n` module. It configures English (en) and
Simplified Chinese (zh-CN) locales, adds a language selector to the header, and internationalizes the index page content using
translation files.

repomix.config.json

@@ -0,0 +1,42 @@
+{
+  "$schema": "https://repomix.com/schemas/latest/schema.json",
+  "input": {
+    "maxFileSize": 52428800
+  },
+  "output": {
+    "filePath": "repomix-output.xml",
+    "style": "xml",
+    "parsableStyle": false,
+    "fileSummary": true,
+    "directoryStructure": true,
+    "files": true,
+    "removeComments": false,
+    "removeEmptyLines": false,
+    "compress": false,
+    "topFilesLength": 5,
+    "showLineNumbers": false,
+    "truncateBase64": false,
+    "copyToClipboard": false,
+    "includeFullDirectoryStructure": false,
+    "tokenCountTree": false,
+    "git": {
+      "sortByChanges": true,
+      "sortByChangesMaxCommits": 100,
+      "includeDiffs": false,
+      "includeLogs": false,
+      "includeLogsCount": 50
+    }
+  },
+  "include": ["pages/index.vue", "i18n/locales/**/*.json", "nuxt.config.ts"],
+  "ignore": {
+    "useGitignore": true,
+    "useDefaultPatterns": true,
+    "customPatterns": []
+  },
+  "security": {
+    "enableSecurityCheck": true
+  },
+  "tokenCount": {
+    "encoding": "o200k_base"
+  }
+}