feat: M1 foundation — compose stack, FastAPI, Google OAuth, encrypted tokens

- docker-compose with Postgres 16 + slim Python API image
- FastAPI app with session middleware, health endpoint, static login page
- Google OAuth (Authlib) with email invite-list whitelist; admin role support
- User + OAuthToken models; refresh tokens encrypted at rest (Fernet)
- Alembic migrations, run automatically on container startup
- Postgres backup/restore scripts for portability between machines

.gitignore

@@ -0,0 +1,28 @@
+# Secrets / local config
+.env
+*.env.local
+
+# Python
+__pycache__/
+*.py[cod]
+.venv/
+venv/
+.mypy_cache/
+.pytest_cache/
+.ruff_cache/
+
+# Node / frontend
+node_modules/
+frontend/dist/
+*.log
+
+# Data / dumps
+*.dump
+*.sql.gz
+backups/
+
+# OS / editor
+.DS_Store
+Thumbs.db
+.idea/
+.vscode/