feat: implement golemancy combat system (spec §6, §9)

- Add ActiveGolem interface and activeGolems to GolemancyState
- Add maxRoomDuration to all 12 golem definitions
- Create golem-combat-actions.ts with pure golem combat logic (summoning, maintenance, attacks, room-duration)
- Create golem-combat.ts pipeline for golem combat setup
- Wire golem maintenance and attacks into processCombatTick
- Wire golem summoning into advanceRoomOrFloor on room entry
- Wire golem room-duration countdown into onFloorCleared callback
- Update combat-actions tests for new processCombatTick signature
- All 921 tests pass, all files under 400-line limit

Closes #259

docs/project-structure.txt

@@ -334,6 +334,7 @@ Mana-Loop/
 │   │   │   │   │   ├── combat-tick.ts
 │   │   │   │   │   ├── enchanting-tick.ts
 │   │   │   │   │   ├── equipment-crafting.ts
+│   │   │   │   │   ├── golem-combat.ts
 │   │   │   │   │   └── pact-ritual.ts
 │   │   │   │   ├── attunementStore.ts
 │   │   │   │   ├── combat-actions.ts
@@ -351,6 +352,7 @@ Mana-Loop/
 │   │   │   │   ├── gameLoopActions.ts
 │   │   │   │   ├── gameStore.ts
 │   │   │   │   ├── gameStore.types.ts
+│   │   │   │   ├── golem-combat-actions.ts
 │   │   │   │   ├── index.ts
 │   │   │   │   ├── manaStore.ts
 │   │   │   │   ├── prestigeStore.ts