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/lib/game/stores/gameStore.ts

@@ -4,7 +4,8 @@
 
 import { create } from 'zustand';
 import { persist } from 'zustand/middleware';
-import { TICK_MS, HOURS_PER_TICK, MAX_DAY, GUARDIANS, getStudySpeedMultiplier } from '../constants';
+import { TICK_MS, HOURS_PER_TICK, MAX_DAY, getStudySpeedMultiplier } from '../constants';
+import { getGuardianForFloor } from '../data/guardian-encounters';
 import { hasSpecial, SPECIAL_EFFECTS } from '../effects/special-effects';
 import { computeEquipmentEffects } from '../effects';
 import type { ComputedEffects } from '../effects/upgrade-effects.types';
@@ -234,7 +235,7 @@ export const useGameStore = create<GameCoordinatorStore>()(
 
         // Pact ritual progress
         if (ctx.prestige.pactRitualFloor !== null) {
-          const guardian = GUARDIANS[ctx.prestige.pactRitualFloor];
+          const guardian = getGuardianForFloor(ctx.prestige.pactRitualFloor);
           if (guardian) {
             const pactAffinityBonus = 1 - (ctx.prestige.prestigeUpgrades.pactAffinity || 0) * 0.1;
             const requiredTime = guardian.pactTime * pactAffinityBonus;
@@ -275,7 +276,8 @@ export const useGameStore = create<GameCoordinatorStore>()(
             1,
             (floor, wasGuardian) => {
               if (wasGuardian) {
-                addLog(`⚔️ ${GUARDIANS[floor]?.name || 'Guardian'} defeated! Visit the Grimoire to sign a pact.`);
+                const defeatedGuardian = getGuardianForFloor(floor);
+                addLog(`\u2694\ufe0f ${defeatedGuardian?.name || 'Guardian'} defeated! Visit the Grimoire to sign a pact.`);
               } else if (floor % 5 === 0) {
                 addLog(`🏰 Floor ${floor} cleared!`);
               }