♻️ refactor: reorganize project structure and centralize search engine config

- Move all source files from root to src/ directory for better organization
- Create src/config/searchEngines.ts to centralize search engine configurations
  - Define unified SearchEngineConfig interface
  - Support both JSONP and Fetch request methods
  - Implement response parsers for Google, Baidu, Bing, DuckDuckGo, and Bilibili
- Refactor src/utils/suggestions.ts to use centralized config
  - Simplify code from 126 lines to 81 lines
  - Support hybrid JSONP/Fetch mode (Bilibili uses Fetch via Vite proxy)
  - Remove duplicate URL construction and parsing logic
- Update path alias configuration
  - Change @/* from ./* to ./src/* in tsconfig.json
  - Update vite.config.ts alias to point to ./src
- Add Bilibili proxy configuration in vite.config.ts for development
- Remove Bilibili rewrites from vercel.json (use Vite proxy instead)
- Add @vercel/node to devDependencies
- Remove unused files: README.md, i18n/README.md, metadata.json, vite-env.d.ts

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

package.json

@@ -15,6 +15,7 @@
   "devDependencies": {
     "@tailwindcss/postcss": "^4.1.17",
     "@types/node": "^22.14.0",
+    "@vercel/node": "^5.5.15",
     "@vitejs/plugin-react": "^5.0.0",
     "autoprefixer": "^10.4.22",
     "postcss": "^8.5.6",