feat: add prettier formatter and MIT license

- Add prettier dev dependency for code formatting
- Create MIT LICENSE file
- Format TypeScript files with prettier
- Update provider order in README (Qwen coder first)
- Update add provider screenshot with new UI

package.json

@@ -21,6 +21,7 @@
     "@types/react": "^18.2.0",
     "@types/react-dom": "^18.2.0",
     "@vitejs/plugin-react": "^4.2.0",
+    "prettier": "^3.6.2",
     "typescript": "^5.3.0",
     "vite": "^5.0.0"
   },