Migrate from Create React App to Vite

CRA (react-scripts 5.0.1) is abandoned and incompatible with TypeScript 5.x.
Vite provides faster builds, active maintenance, and native TS5 support.

- Replace react-scripts with vite + @vitejs/plugin-react
- Move index.html to root with script module entry point
- Replace setupProxy.js with vite.config.ts proxy config
- Rename env vars from REACT_APP_ to VITE_ prefix
- Update tsconfig for bundler module resolution
- Add nginx setup script for deployment

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.env.example

@@ -1,7 +1,7 @@
 # NocoDB (primary data source)
-REACT_APP_NOCODB_URL=http://localhost:8090
-REACT_APP_NOCODB_TOKEN=your_token_here
+VITE_NOCODB_URL=http://localhost:8090
+VITE_NOCODB_TOKEN=your_token_here
 
 # Google Sheets (fallback if NocoDB fails)
-REACT_APP_SHEETS_ID=your_spreadsheet_id_here
-REACT_APP_SHEETS_NAME=Consolidated Data
+VITE_SHEETS_ID=your_spreadsheet_id_here
+VITE_SHEETS_NAME=Consolidated Data