feat(analytics): integrate Google Analytics 4 with GDPR compliance

Prepared the application for Google Analytics 4 tracking with full
GDPR/RODO compliance. GA only loads after user explicitly accepts cookies.

Features:
- Automatic page view tracking on route changes
- Custom event tracking for key user actions
- Privacy-first: GA loads only after cookie consent
- Easy configuration via environment variable
- Comprehensive tracking utilities for common events

Implementation:
- Created analytics.js with GA initialization and event tracking functions
- Created usePageTracking hook for automatic page view tracking
- Integrated GA into App.jsx with AnalyticsWrapper component
- Updated CookieConsent to initialize GA after user consent
- Added VITE_GA_MEASUREMENT_ID to .env.example

Custom events tracked:
- login, sign_up (authentication)
- match_request, match_accepted (matching)
- webrtc_connection, file_transfer (WebRTC)
- event_join, recording_suggestion (events/recording)
- search (search functionality)

Setup:
1. Add VITE_GA_MEASUREMENT_ID=G-XXXXXXXXXX to .env
2. Restart frontend container
3. GA will auto-load after user accepts cookies

Documentation:
- Created comprehensive setup guide in docs/GOOGLE_ANALYTICS_SETUP.md
- Includes troubleshooting, debugging tips, and usage examples

.env.example

@@ -9,3 +9,8 @@ VITE_ALLOWED_HOSTS=localhost,spotlight.cam,.spotlight.cam
 # Cloudflare Turnstile (CAPTCHA)
 # Get your keys from: https://dash.cloudflare.com/
 VITE_TURNSTILE_SITE_KEY=your-site-key-here
+
+# Google Analytics 4
+# Format: G-XXXXXXXXXX
+# Get your measurement ID from: https://analytics.google.com/
+VITE_GA_MEASUREMENT_ID=