Migrate InvoiceService to dependency injection pattern

- Add INVOICE_SERVICE token to DI container
- Register InvoiceService in base module with proper lifecycle
- Update market store to use dependency injection instead of singleton
- Remove exported singleton from InvoiceService class
- Add comprehensive migration documentation with examples
- Maintain type safety with proper TypeScript interfaces

This migration eliminates the legacy singleton pattern and improves:
- Testability through service injection
- Modular architecture with clear boundaries
- Single source of truth for service instances
- Consistent dependency injection patterns

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

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

src/modules/base/index.ts

@@ -14,6 +14,10 @@ import { paymentService } from '@/core/services/PaymentService'
 import { visibilityService } from '@/core/services/VisibilityService'
 import { storageService } from '@/core/services/StorageService'
 import { toastService } from '@/core/services/ToastService'
+import { InvoiceService } from '@/core/services/invoiceService'
+
+// Create service instances
+const invoiceService = new InvoiceService()
 
 /**
  * Base Module Plugin
@@ -44,6 +48,9 @@ export const baseModule: ModulePlugin = {
     // Register toast service
     container.provide(SERVICE_TOKENS.TOAST_SERVICE, toastService)
     
+    // Register invoice service
+    container.provide(SERVICE_TOKENS.INVOICE_SERVICE, invoiceService)
+    
     // Register PWA service
     container.provide('pwaService', pwaService)
 
@@ -92,6 +99,7 @@ export const baseModule: ModulePlugin = {
     visibilityService,
     storageService,
     toastService,
+    invoiceService,
     pwaService
   },