feat: migrate frontend from Vue 3 to React 18 with TanStack ecosystem

- Complete rewrite of frontend using React 18 + TypeScript in strict mode
- Implement TanStack Router for file-based routing matching URL structure
- Use TanStack Query for server state management with smart caching
- Replace Pinia stores with React Context API for auth and UI state
- Adopt Tailwind CSS + shadcn/ui components for consistent styling
- Switch from pnpm to Bun for faster package management and builds
- Configure Vite to support React, TypeScript, and modern tooling
- Create frontend.go with Go embed package for embedding dist/ in binary
- Implement comprehensive TypeScript interfaces (strict mode, no 'any' types)
- Add dark mode support throughout with Tailwind CSS dark: classes
- Set up i18n infrastructure (English translations included)
- Remove all Vue 3 code, components, stores, CSS, and assets
- Includes 18 new files with ~2000 lines of production-ready code

frontend/tsconfig.node.json

@@ -1,17 +1,10 @@
 {
-  "extends": "@tsconfig/node24/tsconfig.json",
-  "include": [
-    "vite.config.*",
-    "vitest.config.*",
-    "cypress.config.*",
-    "nightwatch.conf.*"
-  ],
   "compilerOptions": {
     "composite": true,
-    "noEmit": true,
-    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.node.tsbuildinfo",
+    "skipLibCheck": true,
     "module": "ESNext",
-    "moduleResolution": "Bundler",
-    "types": ["node"]
-  }
+    "moduleResolution": "bundler",
+    "allowSyntheticDefaultImports": true
+  },
+  "include": ["vite.config.ts"]
 }