refactor: extract sub-components from monster functions (issue #99)

- GuardianPactsTab: extracted GuardianCard, PactHeaderSummary, TierFilter + 5 helper components into guardian-pacts-components.tsx
- SpireSummaryTab: extracted TopStatsRow, NextGuardianCard, GuardianRoster, GuardianRosterItem, FloorLegend
- PrestigeTab: extracted InsightSummary, MemoriesCard, PactsCard, ResetLoopSection
- GameStateDebug: extracted WarningBanner, DisplayOptions, GameResetSection, ManaDebugSection, TimeControlSection, QuickActionsSection
- EquipmentCrafter: extracted CraftingProgress, BlueprintCard, BlueprintList, MaterialCard, MaterialsInventory
- PactDebug: extracted GuardianPactRow, GuardianPactList
- GameStateDebugSection: extracted DisplayOptions, GameResetSection, ManaDebugSection, TimeControlSection, QuickActionsSection
- PactDebugSection: extracted GuardianPactRow
- SpireCombatPage: extracted useSpireStats hook
- page.tsx: extracted GrimoireTab to separate file, useGameDerivedStats hook, TabTriggers, LazyTab wrapper

All files now under 400 lines. Build passes. All 639 tests pass.

docs/project-structure.txt

@@ -52,6 +52,7 @@ Mana-Loop/
 │   ├── app/
 │   │   ├── components/
 │   │   │   ├── GameOverScreen.tsx
+│   │   │   ├── GrimoireTab.tsx
 │   │   │   └── LeftPanel.tsx
 │   │   ├── globals.css
 │   │   ├── layout.tsx
@@ -140,6 +141,7 @@ Mana-Loop/
 │   │   │   │   ├── SpireSummaryTab.test.ts
 │   │   │   │   ├── SpireSummaryTab.tsx
 │   │   │   │   ├── StatsTab.tsx
+│   │   │   │   ├── guardian-pacts-components.tsx
 │   │   │   │   └── index.ts
 │   │   │   ├── ActionButtons.tsx
 │   │   │   ├── ActivityLogPanel.tsx