♻️ 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>

vercel.json

@@ -4,12 +4,6 @@
   "devCommand": "pnpm dev",
   "installCommand": "pnpm install",
   "framework": "vite",
-  "rewrites": [
-    {
-      "source": "/bilibili/:path*",
-      "destination": "https://s.search.bilibili.com/main/suggest/:path*"
-    }
-  ],
   "headers": [
     {
       "source": "/(.*)",