launch Bangla polling station finder and prepare repo for GitHub publish

[asimxcode]

This PR adds a complete Bangla-first Polling Station Finder website and prepares the repository for clean GitHub publishing and deployment.

What’s included

• Added full frontend app under site/:
  • Area-based cascading filters (Division -> District -> Upazila -> Constituency -> Union)
  • Bangla NID + DOB lookup flow
  • Realtime center search with autocomplete
  • Nearby center lookup using browser geolocation
  • Party symbol section
  • Responsive UI for desktop/mobile
• Added local constituency map integration:
  • Uses local SVG maps from site/maps/
  • Map display is OFF by default with manual toggle
  • Avoids repeated map thumbnails in default results
• Added data build tooling:
  • scripts/build_web_data.py generates JSON for web app
  • Includes maps_index.json for local map detection
• Added/updated repo docs and publishing files:
  • README.md (rewritten)
  • CONTRIBUTING.md
  • GITHUB_PUBLISHING.md
  • LICENSE (MIT)
  • .gitignore
  • .github/workflows/deploy-pages.yml (GitHub Pages deployment)

How to test

1. Run:
   • python scripts/build_web_data.py
   • python -m http.server 8000 --directory site
2. Open http://localhost:8000
3. Verify:
   • Realtime autocomplete search works
   • Area filter search works
   • NID + DOB demo lookup works
   • Map toggle works (default OFF)
   • Mobile/desktop layout looks correct

Notes

• NID lookup is an open-data approximation (matches probable voter area code by last 6 digits), not private voter-profile verification.