Add teams table, team_memberships table, and team_id column to projects
in the runtime migrations. This fixes startup failures on existing databases
that don't have the teams schema from the migration file.
- Backend: Python 3.12 with FastAPI, SQLAlchemy, boto3
- Frontend: React 18 with TypeScript, Vite build tooling
- Updated Dockerfile for multi-stage Node + Python build
- Updated CI pipeline for Python backend
- Removed old Go code (cmd/, internal/, go.mod, go.sum)
- Updated README with new tech stack documentation
