- Create missing base.html template that user_tokens.html extends
- Add 'API Tokens' navigation link to all templates that were missing it:
  - app/templates/main/matches.html
  - app/templates/main/uploads.html
  - app/templates/upload/fixture.html
  - app/templates/upload/zip.html
- Ensure consistent navigation across all authenticated pages
- Fix PyInstaller packaging by including base.html template

This resolves the template inheritance error and ensures the API Tokens
link is accessible from all pages in the application.