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>

core/backend/requirements.txt

@@ -8,6 +8,7 @@ pydantic==2.10.3
 pydantic-settings==2.7.0
 python-jose[cryptography]==3.3.0
 passlib[bcrypt]==1.7.4
+bcrypt==4.0.1
 python-multipart==0.0.18
 redis[hiredis]==5.2.1
 celery==5.4.0