Remove legacy compatibility layer and enforce modular architecture

- Delete src/stores/market.ts compatibility re-export file
- Update 15 files to import from proper module path @/modules/market/stores/market
- Add necessary type exports to market store for external consumers
- Remove empty src/stores/ directory completely
- Enforce clean modular architecture without global store shortcuts

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/pages/Cart.vue

@@ -47,7 +47,7 @@
 <script setup lang="ts">
 import { computed, onMounted } from 'vue'
 import { useRoute } from 'vue-router'
-import { useMarketStore } from '@/stores/market'
+import { useMarketStore } from '@/modules/market/stores/market'
 import { CheckCircle } from 'lucide-vue-next'
 import ShoppingCart from '@/modules/market/components/ShoppingCart.vue'