feat: banner alerts, consumption predictions, scale improvements, kiosk app

- Banner notification system: suspicious quantities + consumption prediction alerts
- Consumption predictions API: tracks 90-day usage patterns, flags >30% deviations
- Scale stability timeout: 5s → 10s, auto-confirm remains 5s
- Scale integration in edit form: weigh button with inline live display
- Banner edit/weigh actions open edit form directly with scale activation
- Cooking mode: Italian aliases + stem-prefix matching for ingredients
- Recipe regeneration: tracks rejected ingredients for diversity
- Settings migration: localStorage → .env server-side storage
- Expiry priority: mandatory ≤3 days, recommended ≤7 days in recipes
- Scale bug fixes: clear stale weight, double-submit guard, cap deduction
- Android kiosk app (evershelf-kiosk): WebView + embedded BLE scale gateway
- Version bump to 1.4.0

evershelf-kiosk/README.md

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+# EverShelf Kiosk
+
+Android kiosk app that displays the EverShelf web interface in full-screen mode while running the Smart Scale BLE Gateway as a background service.
+
+## Features
+
+- **Full-screen WebView** — displays EverShelf in immersive kiosk mode (no status bar, no navigation)
+- **Built-in Scale Gateway** — BLE connection to smart scales with WebSocket server on port 8765
+- **Auto-reconnect** — automatically reconnects to the last connected scale
+- **Foreground service** — gateway runs even when the screen is off
+- **Camera pass-through** — allows barcode scanning from within the WebView
+- **Error recovery** — shows retry page when the server is unreachable
+
+## Setup
+
+1. Install the APK on your Android tablet/phone
+2. On first launch, grant Bluetooth and Location permissions
+3. Tap the subtle ⚙️ icon in the top-right corner to configure the EverShelf server URL
+4. In EverShelf settings, set the Scale Gateway URL to `ws://localhost:8765`
+
+## Architecture
+
+```
+KioskActivity (WebView — full-screen EverShelf)
+    ↕ binds to
+ScaleGatewayService (foreground service)
+    ├── BleScaleManager (BLE scanning + connection)
+    │   └── ScaleProtocol (multi-protocol weight parser)
+    └── GatewayWebSocketServer (port 8765)
+            ↕ WebSocket
+        WebView (EverShelf JavaScript connects to ws://localhost:8765)
+```
+
+## Building
+
+```bash
+cd evershelf-kiosk
+./gradlew assembleDebug
+# APK at app/build/outputs/apk/debug/app-debug.apk
+```
+
+## Requirements
+
+- Android 7.0+ (API 24)
+- Bluetooth Low Energy support
+- Network access to EverShelf server