fix: unify guardian system references across pact-utils, SpireSummaryTab, PactDebug, and PactDebugSection

- pact-utils.ts: Replace GUARDIANS[floor] with getGuardianForFloor() so pact multipliers work for extended guardians (floors 110+)
- SpireSummaryTab.tsx: Use getGuardianForFloor()/getAllGuardianFloors() instead of static GUARDIANS constant; update type annotations to GuardianDef
- PactDebug.tsx: Use unified guardian lookup; add null guards for getGuardianForFloor return type
- PactDebugSection.tsx: Use unified guardian lookup; add null guards for getGuardianForFloor return type

src/lib/game/utils/pact-utils.ts

@@ -1,6 +1,6 @@
 // ─── Pact Utility Functions ───────────────────────────────────────────────────
 
-import { GUARDIANS } from '../constants';
+import { getGuardianForFloor } from '../data/guardian-encounters';
 
 export function computePactMultiplier(state: {
   signedPacts: number[];
@@ -12,7 +12,7 @@ export function computePactMultiplier(state: {
 
   let baseMult = 1.0;
   for (const floor of signedPacts) {
-    const guardian = GUARDIANS[floor];
+    const guardian = getGuardianForFloor(floor);
     if (guardian) {
       baseMult *= guardian.damageMultiplier;
     }
@@ -43,7 +43,7 @@ export function computePactInsightMultiplier(state: {
 
   let mult = 1.0;
   for (const floor of signedPacts) {
-    const guardian = GUARDIANS[floor];
+    const guardian = getGuardianForFloor(floor);
     if (guardian) {
       mult *= guardian.insightMultiplier;
     }