feat: Major updates to backend structure and security enhancements

- Removed `COMMON_ERRORS.md` file to streamline documentation.
- Added `Flask-Limiter` for rate limiting and `redis` for session management in `requirements.txt`.
- Expanded `ROADMAP.md` to include completed security features and planned enhancements for version 2.2.
- Enhanced `setup_myp.sh` for ultra-secure kiosk installation, including system hardening and security configurations.
- Updated `app.py` to integrate CSRF protection and improved logging setup.
- Refactored user model to include username and active status for better user management.
- Improved job scheduler with uptime tracking and task management features.
- Updated various templates for a more cohesive user interface and experience.

backend/app/static/js/service-worker.js

@@ -0,0 +1,82 @@
+// Backup Service Worker for MYP Platform
+const CACHE_NAME = 'myp-platform-backup-v1';
+
+// Assets to cache
+const ASSETS_TO_CACHE = [
+  '/',
+  '/dashboard',
+  '/static/css/tailwind.min.css',
+  '/static/css/tailwind-dark.min.css',
+  '/static/js/ui-components.js',
+  '/static/js/offline-app.js',
+  '/static/favicon.ico'
+];
+
+// Install event - cache core assets
+self.addEventListener('install', (event) => {
+  console.log('Backup SW: Installing...');
+  
+  event.waitUntil(
+    caches.open(CACHE_NAME)
+      .then((cache) => {
+        console.log('Backup SW: Caching assets');
+        return cache.addAll(ASSETS_TO_CACHE);
+      })
+      .then(() => {
+        console.log('Backup SW: Assets cached');
+        return self.skipWaiting();
+      })
+  );
+});
+
+// Activate event - clean up old caches
+self.addEventListener('activate', (event) => {
+  console.log('Backup SW: Activating...');
+  
+  event.waitUntil(
+    caches.keys()
+      .then((cacheNames) => {
+        return Promise.all(
+          cacheNames.map((cacheName) => {
+            if (cacheName !== CACHE_NAME) {
+              console.log('Backup SW: Deleting old cache', cacheName);
+              return caches.delete(cacheName);
+            }
+          })
+        );
+      })
+      .then(() => {
+        console.log('Backup SW: Activated');
+        return self.clients.claim();
+      })
+  );
+});
+
+// Fetch event - cache first, network fallback
+self.addEventListener('fetch', (event) => {
+  event.respondWith(
+    caches.match(event.request)
+      .then((response) => {
+        if (response) {
+          return response;
+        }
+        
+        return fetch(event.request)
+          .then((fetchResponse) => {
+            // Don't cache non-success responses
+            if (!fetchResponse || fetchResponse.status !== 200 || fetchResponse.type !== 'basic') {
+              return fetchResponse;
+            }
+            
+            // Cache successful responses
+            const responseToCache = fetchResponse.clone();
+            caches.open(CACHE_NAME)
+              .then((cache) => {
+                cache.put(event.request, responseToCache);
+              });
+              
+            return fetchResponse;
+          });
+      })
+  );
+});