feat: add customer-owned frontend, device config, pricing (v1.2.0)

- Add frontend/ at root (customer's own React app, all pages)
- Add customers/tianpu/devices.json (17 devices, 375kW PV)
- Add customers/tianpu/pricing.json (Beijing TOU 4-tier)
- Add customers/tianpu/hooks/__init__.py
- Add .githooks/pre-commit to block core/ modifications
- Add CLAUDE.md, .gitignore
- Update docker-compose.override.yml frontend -> ./frontend
- Pin bcrypt==4.0.1 in requirements.txt

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/Dockerfile

@@ -0,0 +1,11 @@
+FROM node:20-alpine
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install
+
+COPY . .
+
+EXPOSE 3000
+CMD ["npm", "run", "dev", "--", "--host", "0.0.0.0"]