feat: add composable data and auth layers

[leynier]

Summary

• add bounded dependencies and lazy adapters for SQL, document, vector, graph and cache engines
• generate SQLModel/SQLAlchemy metadata plus Alembic migrations
• add API-key, OIDC and Supabase authentication helpers
• make provider SDK usage explicit and enforce deptry in every affected preset

Validation

• uv run pytest -n auto -q (65 passed)
• local gh act lint and presets passed
• local structure job reached a transient Docker registry authentication error; the equivalent native suite passed and hosted Actions is authoritative