Update index.html

- Updated <script> entrypoint to use `/src/main.tsx` instead of `/quantumca/src/main.tsx`
  to ensure Vite correctly rewrites paths during build.
- Added richer <meta name="keywords"> to improve SEO discoverability.
- Included Open Graph image (`og:image`) for better link previews on social platforms.
- Verified that Vite will handle rewriting the asset paths to `/quantumca/assets/...`
  automatically during the production build for GitHub Pages.
- This resolves the Rollup build error and ensures the app loads correctly after deployment.

Author: FutureTechVision-Global