test: add cross-module integration tests for tick pipeline

Add 38 integration tests split across 4 files (all under 400 lines):
- cross-module-helpers.ts: shared resetAllStores() and tickN() utilities
- cross-module-combat-meditation.test.ts (12 tests): combat floor
  clearing, meditation regen flow, incursion effects, convert action
- cross-module-prestige-discipline.test.ts (15 tests): prestige loop
  reset, discipline mana drain/XP, pact ritual completion
- cross-module-lifecycle-consistency.test.ts (11 tests): full loop
  lifecycle, store consistency invariants, pause/gameOver blocking

All 38 new + 112 existing tests pass.

docs/project-structure.txt

@@ -199,6 +199,10 @@ Mana-Loop/
 │       │   │   ├── crafting-utils-equipment.test.ts
 │       │   │   ├── crafting-utils-recipe.test.ts
 │       │   │   ├── crafting-utils-time.test.ts
+│       │   │   ├── cross-module-combat-meditation.test.ts
+│       │   │   ├── cross-module-helpers.ts
+│       │   │   ├── cross-module-lifecycle-consistency.test.ts
+│       │   │   ├── cross-module-prestige-discipline.test.ts
 │       │   │   ├── discipline-math.test.ts
 │       │   │   ├── discipline-prerequisites.test.ts
 │       │   │   ├── enemy-barrier-utils.test.ts