Add the first-shift tutorial design and state machine

Write the eight-beat tutorial sheet, its safe visitor script, persistence and
replay rules. Add a deterministic, skippable/restartable Tutorial RefCounted
state machine with headless tests. UI/GameManager wiring remains the next task.
Headless 235/235, Python 94/94.

README.md

@@ -108,6 +108,7 @@ Full setup, every run/test/smoke command, and the controls table are in
 - [`CHANGELOG.md`](CHANGELOG.md) — User-facing changes by version.
 - [`docs/architecture.md`](docs/architecture.md) — arc42-style architecture documentation.
 - [`docs/gameplay.md`](docs/gameplay.md) — Gameplay systems, venues, and the escalation model.
+- [`docs/tutorial.md`](docs/tutorial.md) — First-shift tutorial beats and rules.
 - [`docs/asset-tooling.md`](docs/asset-tooling.md) — Asset pipelines, model tools, and screenshot gates.
 - [`docs/getting-started.md`](docs/getting-started.md) — Setup, run/test commands, and controls.
 - [`docs/development-status.md`](docs/development-status.md) — Implemented features and what's next.