Replace the 5-room demo with a condensed 14-room manor on one spine
(restore power -> escape) that stacks all five mechanics, plus an optional
spirit thread feeding 3 prioritized endings (no hard-fail). Pure YAML on the
existing engines: 14 rooms across 3 levels, ~16 items, 5 combinations, the
old_man hint NPC, restore_power + lay_to_rest quests, and 3 endings.
Consolidate to one world: remove the toy "Test Manor" test fixture so the
loader tests exercise the real shipped world. Adapt WorldLoaderTest and
TutorialLoaderTest to form-invariants of the real world, and add
WorldSolvableTest, which walks the critical path (light/lock gating +
Combinations.tryUse + flags) to guarantee power_on, ghost_banished, and a
victory ending are reachable — an unsolvable world now fails the build.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
