Fix Dockerfile build error

- Remove obsolete reference to scripts/add-mqtt-tables.js
- MQTT tables are now created in init-database.js
- Fixes Docker build failure

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Dockerfile

@@ -20,9 +20,8 @@ COPY . .
 # Build Next.js App
 RUN npm run build
 
-# Initialisiere Datenbanken
-RUN npm run db:init && \
-    node scripts/add-mqtt-tables.js
+# Initialisiere Datenbanken (MQTT tables included in init-database.js)
+RUN npm run db:init
 
 # Runner Stage
 FROM base AS runner