refactor: remove GUARDIANS constant, consolidate into guardian-data.ts

- Delete src/lib/game/constants/guardians.ts (the old static GUARDIANS constant)
- Create src/lib/game/data/guardian-data.ts with BASE_GUARDIANS (same data, new home)
- Remove GUARDIANS export from constants/index.ts
- Update all 11 files that imported GUARDIANS to use getGuardianForFloor() or BASE_GUARDIANS:
  - useGameDerived.ts, combat-actions.ts, gameStore.ts, prestigeStore.ts
  - combat-utils.ts, room-utils.ts, floor-utils.ts, spire-utils.ts
  - SpireCombatPage.tsx, SpireHeader.tsx
- Update 4 test files to use getGuardianForFloor() instead of GUARDIANS constant
- guardian-encounters.ts now imports BASE_GUARDIANS from guardian-data.ts
- Split room-utils.test.ts (505 lines) into room-utils.test.ts + room-utils-floor-state.test.ts

src/components/game/tabs/SpireCombatPage/SpireCombatPage.tsx

@@ -6,8 +6,7 @@ import { useCombatStore, useManaStore, usePrestigeStore, fmt, computeMaxMana, co
 import { computeDisciplineEffects } from '@/lib/game/effects/discipline-effects';
 import { getUnifiedEffects } from '@/lib/game/effects';
 import { useCraftingStore } from '@/lib/game/stores/craftingStore';
-import { GUARDIANS } from '@/lib/game/constants';
-import { getExtendedGuardian, isGuardianFloor } from '@/lib/game/data/guardian-encounters';
+import { getGuardianForFloor, isGuardianFloor } from '@/lib/game/data/guardian-encounters';
 import { getRoomsForFloor, generateSpireFloorState } from '@/lib/game/utils/spire-utils';
 import { SpireHeader } from './SpireHeader';
 import { RoomDisplay } from './RoomDisplay';
@@ -122,7 +121,7 @@ export function SpireCombatPage() {
       setClearedFloor(currentFloor, true);
 
       if (wasGuardian) {
-        const guardian = GUARDIANS[currentFloor] || getExtendedGuardian(currentFloor);
+        const guardian = getGuardianForFloor(currentFloor);
         if (guardian) {
           addActivityLog('enemy_defeated', `⚔️ ${guardian.name} defeated!`, {
             enemyName: guardian.name,