Initial commit: StackPilot Phase 1 (Core)

Self-hosted Docker Compose manager.
- Backend: FastAPI + docker-py + SQLite (JWT auth, file-first stacks,
  lifecycle, live status, WebSocket logs, docker-run converter, audit log)
- Frontend: React + Vite + Tailwind (login/setup, dashboard, stacks,
  stack detail, Monaco editor, dark/light theme)
- Deployment: docker-compose.yml, Dockerfiles, nginx reverse proxy

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/models/__init__.py

@@ -0,0 +1,6 @@
+"""SQLModel table models. Importing this package registers all tables."""
+from models.audit import AuditLog
+from models.stack import Stack
+from models.user import User
+
+__all__ = ["User", "Stack", "AuditLog"]