Progressive web app

[LaGodxy]

Description

✅ PWA Implementation Complete
This PR delivers a Progressive Web App (PWA) implementation for Veritix, providing offline capabilities, native app-like experiences, push notifications, and background synchronization.
The platform now works seamlessly offline, supports app installation, and ensures reliable access to tickets, events, and user data across devices.

Related Issues

Closes #325

Changes Made

• Core PWA Features

  • Service Worker (/public/sw.js) – Offline functionality with cache-first and network-first strategies
  • Web App Manifest (/public/manifest.json) – App installation with icons, shortcuts, and metadata
  • Offline Page (/public/offline.html) – Fallback page with feature overview
  • PWA Client Library (/public/js/pwa.js) – Frontend integration and management

• Backend Infrastructure

  • Entities: 6 PWA-related models for subscriptions, notifications, sync jobs, analytics, cache, and offline data
  • Services: 5 services implementing offline event discovery, push notifications, background sync, and analytics
  • Controllers: 2 controllers with 50+ REST API endpoints for PWA management
  • Module Integration: Complete NestJS module integration
  • Tests: Comprehensive unit tests for all services and controllers

• Key Capabilities Implemented

  • ✅ Offline Ticket Access – View tickets and QR codes without internet
  • ✅ Push Notifications – Event updates and reminders with VAPID support
  • ✅ Background Sync – Automatic data synchronization when back online
  • ✅ Offline Event Discovery – Browse cached events with search and filtering
  • ✅ Install Prompts – Native app-like installation experience
  • ✅ Analytics Tracking – PWA usage and performance metrics

• Technical Highlights

  • Cache-first strategy for static assets
  • Network-first strategy for API calls with offline fallback
  • IndexedDB integration for client-side data storage
  • Background sync with exponential backoff retry logic
  • Multi-platform responsive design
  • Security via VAPID keys and encrypted subscriptions

How to Test

1. Install the PWA via supported browser → confirm install prompt appears.
2. Open Veritix offline → verify offline page loads and cached events/tickets are accessible.
3. Trigger push notifications → confirm delivery when online.
4. Perform offline actions → reconnect and verify background sync updates data correctly.
5. Test endpoints via controllers → validate 50+ REST API routes function as expected.
6. Run unit tests → confirm all PWA services/controllers pass.

Screenshots (if applicable)

N/A (mainly PWA behavior and offline capabilities).

Checklist

• Code follows project coding style
• All PWA features tested locally
• Documentation updated (README.md)
• Unit tests implemented for services and controllers
• Environment configuration (VAPID keys, service worker) verified