v0.3.3

Scaffold fixes from the my-stockflow F1 analysis:

• Repository-layer session door (P5): the scaffold now ships app/repositories/session.py (get_session) and removes get_db from app/database.py (now pure infrastructure: engine/SessionLocal/Base). A service-backed feature's boundary obtains its session through a service re-exporting get_session from the repository layer, so a route never imports the DB session from infrastructure (the recurring layering-violation refactor).
• Playwright worker-port persistence (P6): resolvePort persists the self-allocated free port into process.env, so Playwright's test workers (which re-evaluate the config) reuse it instead of allocating a divergent port that points the browser where nothing is listening (the 'home/About specs not reachable' bug).