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/core/di-container.ts

@@ -134,6 +134,9 @@ export const SERVICE_TOKENS = {
   
   // Events services
   EVENTS_SERVICE: Symbol('eventsService'),
+  
+  // Invoice services
+  INVOICE_SERVICE: Symbol('invoiceService'),
 } as const
 
 // Type-safe injection helpers

src/core/services/invoiceService.ts

@@ -32,7 +32,7 @@ export interface PaymentStatus {
   payment_hash: string
 }
 
-class InvoiceService {
+export class InvoiceService {
   private baseUrl: string
 
   constructor() {
@@ -186,6 +186,3 @@ class InvoiceService {
   }
 }
 
-// Export singleton instance
-export const invoiceService = new InvoiceService()
-

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
   },
 

src/modules/market/stores/market.ts

@@ -1,11 +1,10 @@
 import { defineStore } from 'pinia'
 import { ref, computed, readonly, watch } from 'vue'
-import { invoiceService } from '@/core/services/invoiceService'
 import { paymentMonitor } from '../services/paymentMonitor'
 import { nostrmarketService } from '../services/nostrmarketService'
 import { useAuth } from '@/composables/useAuthService'
 import { injectService, SERVICE_TOKENS } from '@/core/di-container'
-import type { LightningInvoice } from '@/core/services/invoiceService'
+import type { LightningInvoice, InvoiceService } from '@/core/services/invoiceService'
 
 
 import type {
@@ -18,6 +17,7 @@ import type {
 export const useMarketStore = defineStore('market', () => {
   const auth = useAuth()
   const storageService = injectService(SERVICE_TOKENS.STORAGE_SERVICE) as any
+  const invoiceService = injectService(SERVICE_TOKENS.INVOICE_SERVICE) as InvoiceService
   // Core market state
   const markets = ref<Market[]>([])
   const stalls = ref<Stall[]>([])