Implement Bodenfeuchte app: MQTT listener, SQLite storage, chart UI, Docker

- Custom Next.js server starts MQTT listener on boot
- Subscribes to zigbee2mqtt/Bodenfeuchte_1, stores soil_moisture in SQLite
- API route /api/data returns last 6 hours of measurements
- Frontend shows current value + Recharts line chart, auto-refresh every 60s
- Dockerfile + docker-compose with persistent volume for SQLite DB

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

Dockerfile

@@ -0,0 +1,27 @@
+FROM node:20-alpine AS deps
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci --omit=dev
+
+FROM node:20-alpine AS builder
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+RUN npx tsc --project tsconfig.server.json
+
+FROM node:20-alpine AS runner
+WORKDIR /app
+ENV NODE_ENV=production
+
+COPY --from=deps /app/node_modules ./node_modules
+COPY --from=builder /app/.next ./.next
+COPY --from=builder /app/dist ./dist
+COPY --from=builder /app/public ./public
+COPY package*.json ./
+
+RUN mkdir -p data
+
+EXPOSE 3000
+CMD ["node", "dist/server.js"]