feat: extend PWA offline support to all recipe routes and glaube pages

- Add offline support for category, tag, icon list pages
- Add offline support for favorites page (stores locally for offline)
- Add offline support for season list page
- Cache root page and glaube pages for offline access
- Dynamically discover glaube routes at build time using Vite glob
- Add db functions for getAllCategories, getAllTags, getAllIcons
- Pre-cache __data.json for all category, tag, icon, season subroutes
- Update service worker to cache glaube and root page responses

src/routes/[recipeLang=recipeLang]/favorites/+page.ts

@@ -0,0 +1,78 @@
+import type { PageLoad } from "./$types";
+import { browser } from '$app/environment';
+import { isOffline, canUseOfflineData } from '$lib/offline/helpers';
+import { getAllBriefRecipes, isOfflineDataAvailable } from '$lib/offline/db';
+
+// Store favorites in localStorage for offline access
+const FAVORITES_STORAGE_KEY = 'bocken-favorites';
+
+function getStoredFavorites(): string[] {
+    if (!browser) return [];
+    try {
+        const stored = localStorage.getItem(FAVORITES_STORAGE_KEY);
+        return stored ? JSON.parse(stored) : [];
+    } catch {
+        return [];
+    }
+}
+
+function storeFavorites(favoriteIds: string[]): void {
+    if (!browser) return;
+    try {
+        localStorage.setItem(FAVORITES_STORAGE_KEY, JSON.stringify(favoriteIds));
+    } catch {
+        // Storage full or unavailable
+    }
+}
+
+export const load: PageLoad = async ({ data, params }) => {
+    const isEnglish = params.recipeLang === 'recipes';
+
+    // If we have server data, store the favorite IDs for offline use
+    if (data?.favorites && Array.isArray(data.favorites) && data.favorites.length > 0) {
+        const favoriteIds = data.favorites.map((r: any) => r.short_name);
+        storeFavorites(favoriteIds);
+    }
+
+    // Check if we should use offline data
+    const shouldUseOffline = browser && (isOffline() || data?.isOffline) && canUseOfflineData();
+
+    if (shouldUseOffline) {
+        try {
+            const hasOfflineData = await isOfflineDataAvailable();
+            if (hasOfflineData) {
+                const storedFavoriteIds = getStoredFavorites();
+
+                if (storedFavoriteIds.length === 0) {
+                    return {
+                        ...data,
+                        favorites: [],
+                        isOffline: true,
+                        offlineMessage: isEnglish
+                            ? 'Favorites are not available offline. Please sync while online first.'
+                            : 'Favoriten sind offline nicht verfügbar. Bitte zuerst online synchronisieren.'
+                    };
+                }
+
+                const allRecipes = await getAllBriefRecipes();
+                const favorites = allRecipes
+                    .filter(recipe => storedFavoriteIds.includes(recipe.short_name))
+                    .map(recipe => ({ ...recipe, isFavorite: true }));
+
+                return {
+                    ...data,
+                    favorites,
+                    isOffline: true
+                };
+            }
+        } catch (error) {
+            console.error('Failed to load offline favorites:', error);
+        }
+    }
+
+    // Return server data as-is
+    return {
+        ...data,
+        isOffline: false
+    };
+};