feat: Recreate Spire Combat Page — full spire climbing experience

- Add guardian-encounters.ts: Extended guardian definitions for all mana types (compound, exotic, combo) with dynamic name generation
- Add spire-utils.ts: Spire-specific utilities (room generation, enemy stat scaling, insight calculation)
- Add enemy-generator.ts: Enemy generation with combinable modifiers (mage, shield, armored, swarm, agile)
- Add SpireCombatPage/ directory with modular sub-components:
  - SpireHeader.tsx: Floor info, climb controls, exit button, HP/room progress bars
  - RoomDisplay.tsx: Current room info with enemies, barriers, armor, dodge stats
  - SpireCombatControls.tsx: Spell selection panel, golem status panel
  - SpireActivityLog.tsx: Combat activity log
  - SpireManaDisplay.tsx: Compact mana display with elemental pools
- Modify page.tsx: Conditionally render SpireCombatPage when spireMode is true
- Add comprehensive tests (49 tests) for spire utilities, guardian encounters, and enemy generation

src/app/page.tsx

@@ -53,6 +53,7 @@ const GolemancyTab = lazy(() => import('@/components/game/tabs').then(module =>
 const GuardianPactsTab = lazy(() => import('@/components/game/tabs').then(module => ({ default: module.GuardianPactsTab })));
 const SpireSummaryTab = lazy(() => import('@/components/game/tabs').then(module => ({ default: module.SpireSummaryTab })));
 const CraftingTab = lazy(() => import('@/components/game/tabs').then(module => ({ default: module.CraftingTab })));
+const SpireCombatPage = lazy(() => import('@/components/game/tabs/SpireCombatPage').then(module => ({ default: module.SpireCombatPage })));
 
 const TabLoadingFallback = () => <div className="p-4 text-center text-gray-400">Loading...</div>;
 
@@ -217,6 +218,17 @@ export default function ManaLoopGame() {
 
   if (!mounted) return <div className="p-4 text-center text-gray-400">Loading...</div>;
 
+  // Spire mode: full-page replacement view
+  if (spireMode) {
+    return (
+      <ErrorBoundary>
+        <Suspense fallback={<div className="p-4 text-center text-gray-400">Loading spire...</div>}>
+          <SpireCombatPage />
+        </Suspense>
+      </ErrorBoundary>
+    );
+  }
+
   return (
     <ErrorBoundary>
       <TooltipProvider>