Add NextSnap PWA with photo gallery viewer and continuous capture

Offline-first photo capture app for Nextcloud with:
- Camera capture with continuous mode (auto-reopens after each photo)
- File browser with fullscreen image gallery, swipe navigation, and rename
- Upload queue with background sync engine
- Admin panel for Nextcloud user management
- Service worker for offline-first caching (v13)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/static/js/storage.js

@@ -0,0 +1,152 @@
+// NextSnap - IndexedDB Storage using Dexie.js
+'use strict';
+
+const Storage = {
+    db: null,
+    
+    init() {
+        // Initialize Dexie database
+        this.db = new Dexie('nextsnap');
+        
+        // Define schema with compound indexes
+        this.db.version(1).stores({
+            photos: '++id, username, timestamp, filename, targetPath, status, [username+status], [username+timestamp]',
+            settings: '++id, username, [username+key]'
+        });
+        
+        return this.db.open();
+    },
+    
+    async savePhoto(photoData) {
+        /**
+         * Save a photo to IndexedDB
+         * photoData: {
+         *   username: string,
+         *   timestamp: number,
+         *   filename: string,
+         *   targetPath: string,
+         *   blob: Blob,
+         *   status: 'pending' | 'uploading' | 'uploaded' | 'verified'
+         *   retryCount: number,
+         *   lastError: string
+         * }
+         */
+        const id = await this.db.photos.add({
+            username: photoData.username,
+            timestamp: photoData.timestamp,
+            filename: photoData.filename,
+            targetPath: photoData.targetPath,
+            blob: photoData.blob,
+            status: photoData.status || 'pending',
+            retryCount: photoData.retryCount || 0,
+            lastError: photoData.lastError || null
+        });
+        
+        return id;
+    },
+    
+    async getPhoto(id) {
+        return await this.db.photos.get(id);
+    },
+    
+    async getAllPhotos(username = null) {
+        if (username) {
+            return await this.db.photos
+                .where('username').equals(username)
+                .reverse()
+                .sortBy('timestamp');
+        }
+        return await this.db.photos.reverse().sortBy('timestamp');
+    },
+    
+    async getPendingPhotos(username = null) {
+        if (username) {
+            return await this.db.photos
+                .where('[username+status]')
+                .equals([username, 'pending'])
+                .sortBy('timestamp');
+        }
+        return await this.db.photos
+            .where('status').equals('pending')
+            .sortBy('timestamp');
+    },
+    
+    async getRecentPhotos(username, limit = 5) {
+        return await this.db.photos
+            .where('username').equals(username)
+            .reverse()
+            .limit(limit)
+            .sortBy('timestamp');
+    },
+    
+    async updatePhoto(id, updates) {
+        return await this.db.photos.update(id, updates);
+    },
+    
+    async deletePhoto(id) {
+        return await this.db.photos.delete(id);
+    },
+    
+    async getPhotoCount(username = null, status = null) {
+        let collection = this.db.photos;
+        
+        if (username && status) {
+            return await collection
+                .where('[username+status]')
+                .equals([username, status])
+                .count();
+        } else if (username) {
+            return await collection
+                .where('username').equals(username)
+                .count();
+        } else if (status) {
+            return await collection
+                .where('status').equals(status)
+                .count();
+        }
+        
+        return await collection.count();
+    },
+    
+    async saveSetting(username, key, value) {
+        // Check if setting exists
+        const existing = await this.db.settings
+            .where('[username+key]')
+            .equals([username, key])
+            .first();
+        
+        if (existing) {
+            await this.db.settings.update(existing.id, { value: value });
+        } else {
+            await this.db.settings.add({
+                username: username,
+                key: key,
+                value: value
+            });
+        }
+    },
+    
+    async getSetting(username, key, defaultValue = null) {
+        const setting = await this.db.settings
+            .where('[username+key]')
+            .equals([username, key])
+            .first();
+        
+        return setting ? setting.value : defaultValue;
+    },
+    
+    async clearVerifiedPhotos(username = null) {
+        if (username) {
+            return await this.db.photos
+                .where('[username+status]')
+                .equals([username, 'verified'])
+                .delete();
+        }
+        return await this.db.photos
+            .where('status').equals('verified')
+            .delete();
+    }
+};
+
+// Make Storage globally available
+window.Storage = Storage;