[Feature] Implement PWA Manifest, SEO Enhancements, and Brand Logo

### Is your feature request related to a problem? Please describe.
Currently, the application lacks standard PWA configuration (`manifest.json`), proper SEO meta tags, and consistent branding assets (Logo) in the frontend.
- **SEO:** The lack of meta tags affects search engine discoverability and social media sharing previews.
- **PWA:** Users cannot "install" the application on their Desktop or Mobile devices because the manifest is missing.
- **Branding:** The official DebateAI logo is not consistently used as the favicon or app icon.

### Describe the solution you'd like
I propose implementing the following enhancements to the Frontend:

1. **PWA Support:** Add a `manifest.json` file to define the app name, icons, theme colors, and display mode (standalone).
2. **SEO Optimization:** Add standard `` tags (Description, Keywords, Open Graph, Twitter Cards) to the `index.html` or main layout.
3. **Branding:** Add the official DebateAI logo assets and link them correctly as favicons and manifest icons.

### Proposed Implementation
- Create `public/manifest.json` with standard PWA fields (`short_name`, `icons`, `start_url`, `theme_color`).
- Update the `` section in the entry file to include SEO scripts.
- Ensure the specific `DebateAI` logo is added to the public assets folder.

### Benefits
- **Installability:** Enables "Add to Home Screen" functionality for mobile and desktop users.
- **Discoverability:** Improves ranking on search engines and appearance on social platforms.
- **Professionalism:** Provides a polished, branded experience for users.