fix: Spire tab maxFloorReached undefined error

docs/context-spire-tab-fix.md

@@ -0,0 +1,36 @@
+# Context: Spire Tab "maxFloorReached" Error Fix
+
+## Problem Statement
+The Spire tab fails to load with error: `TypeError: Cannot read properties of undefined (reading 'maxFloorReached')`
+
+## Error Analysis
+This error indicates that the code is trying to access `maxFloorReached` on an undefined object. Likely causes:
+1. Missing or undefined combat store state
+2. Incorrect access of combat state in SpireTab.tsx
+3. Race condition in store initialization
+4. Legacy store references in Spire tab components
+
+## Key Files to Investigate/Modify
+- `src/components/game/tabs/SpireTab.tsx` - Spire tab component
+- `src/lib/game/stores/combatStore.ts` - Combat state (contains maxFloorReached)
+- `src/lib/game/stores/index.ts` - Store exports
+- `src/components/game/tabs/SpireHeader.tsx` - Spire header component
+- `src/components/game/tabs/FloorControls.tsx` - Floor control components
+
+## Architecture Rules (from AGENTS.md)
+- Use modular stores: import `useCombatStore` from `src/lib/game/stores/`
+- NEVER import from legacy `src/lib/game/store.ts` or `src/lib/game/store/`
+- All files must stay under 400 lines
+- Use Zustand store hooks properly (avoid direct getState() in render)
+
+## Debugging Steps
+1. Check SpireTab.tsx for undefined state access
+2. Verify combatStore.ts has `maxFloorReached` properly initialized
+3. Ensure store subscriptions are correctly set up
+4. Check for race conditions in component mounting
+
+## Expected Outcome
+- Spire tab loads without errors
+- `maxFloorReached` is properly accessed from combatStore
+- All legacy store references in Spire-related files are removed
+- Regression test added to `src/lib/game/stores/__tests__/combat-store-tests/`