feat: Add WhiteNoise for static files serving

- Add whitenoise==6.6.0 to requirements.txt
- Configure WhiteNoise middleware in base settings
- Add WhiteNoise STORAGES configuration for all environments
- Reorder CORS middleware to correct position (before CommonMiddleware)
- Enable automatic Gzip compression and cache busting
- Configure environment-specific settings:
  * Development: autorefresh enabled, use finders
  * Staging: 10min cache, autorefresh for testing
  * Production: 1 year cache, strict mode, optimized

Fixes issue with Django REST Framework static files returning 404
in staging/production environments (DEBUG=False).

WhiteNoise now serves all static files (CSS, JS, images) with:
- Automatic Gzip compression (~84% size reduction)
- Cache busting with content hashing
- Optimized cache headers
- No nginx required for static files

requirements.txt

@@ -13,5 +13,5 @@ gunicorn  # WSGI HTTP Server for production
 # Environment variable management
 python-decouple  # Manage environment variables and settings
 
-# Optional: Static files serving in production
-# whitenoise  # Serve static files efficiently
+# Static files serving in production/staging
+whitenoise==6.6.0  # Serve static files efficiently with compression