<reusable-compact filename="ARCHITECTURE.md">
Flask app factory: `from app import create_app`; supports isolated overrides including `TESTING` and `DATABASE`. HTTP routes live in `app.routes`; SQLite access is confined to typed `app.persistence`; templates/static assets live under `app/`; tests use pytest; `bin/test.sh` runs the complete suite. Root `/` must return 200, and independent app instances must not share state.
</reusable-compact>

RESULT: SUCCESS

FILES CHANGED:
- .env.example
- .gitignore
- app/__init__.py
- app/persistence.py
- app/routes.py
- app/templates/base.html
- app/templates/index.html
- app/static/css/style.css
- bin/test.sh
- config.py
- pyproject.toml
- pytest.ini
- run.py
- tests/conftest.py
- tests/test_architecture.py
- tests/test_routes.py
- uv.lock

SUMMARY:
Implemented the Flask application factory, isolated SQLite persistence boundary, route registration, templates, configuration, tests, and POSIX test launcher. `sh bin/test.sh` passes all 5 tests; Ruff also passes.

BLOCKERS:
- None