Develop (#55)

feat: optimize dashboard/search UX and simplify extension architecture

Redesign Dashboard with compact tool grid and recently used tools
Improve TopBar search UX with Cmd/Ctrl+K shortcut and better history navigation
Reorganize project structure into src/
Migrate i18n from react-i18next to chrome.i18n
Remove runtime language switch and settings page
Remove HTML/Markdown conversion tools
Clean up unused code, dead animations, redundant comments, and imports
Improve component consistency with shadcn/ui patterns
Replace hardcoded strings/colors with i18n tokens and theme tokens
Add comprehensive project documentation and coding standards
Fix CI artifact upload workflow and multiple TypeScript/test issues

Includes various refactors, UI polish, i18n cleanup, CI improvements,
and maintenance updates across the codebase.

src/providers/AppRoot.tsx

@@ -0,0 +1,17 @@
+import React from 'react';
+import { ThemeModeProvider } from './ThemeModeProvider';
+import { RouterProvider } from './RouterProvider';
+
+interface AppRootProps {
+  children: React.ReactNode;
+}
+
+export default function AppRoot({ children }: AppRootProps) {
+  return (
+    <React.StrictMode>
+      <ThemeModeProvider>
+        <RouterProvider>{children}</RouterProvider>
+      </ThemeModeProvider>
+    </React.StrictMode>
+  );
+}