Refactor authentication architecture to eliminate dual auth complexity

This major refactor consolidates the authentication system to use a single
source of truth, eliminating timing issues and architectural complexity
that was causing chat and payment functionality problems.

Key Changes:
• Remove old global useAuth composable and replace with useAuthService wrapper
• Update all 25+ files to use consistent auth pattern via dependency injection
• Eliminate dual auth detection workarounds from services (ChatService, PaymentService, etc.)
• Fix TypeScript errors and add proper Uint8Array conversion for Nostr private keys
• Consolidate auth state management to AuthService as single source of truth

Benefits:
• Resolves chat peer loading and message subscription timing issues
• Fixes wallet detection problems for Lightning payments
• Eliminates race conditions between global and injected auth
• Maintains API compatibility while improving architecture
• Reduces code complexity and improves maintainability

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

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

src/modules/market/composables/useMarket.ts

@@ -5,7 +5,7 @@ import { config } from '@/lib/config'
 import { nostrmarketService } from '../services/nostrmarketService'
 import { nip04 } from 'nostr-tools'
 import { useAsyncOperation } from '@/core/composables/useAsyncOperation'
-import { auth } from '@/composables/useAuth'
+import { auth } from '@/composables/useAuthService'
 
 // Nostr event kinds for market functionality
 const MARKET_EVENT_KINDS = {

src/modules/market/composables/usePaymentStatusChecker.ts

@@ -1,5 +1,5 @@
 import { ref } from 'vue'
-import { useAuth } from '@/composables/useAuth'
+import { useAuth } from '@/composables/useAuthService'
 import { useMarketStore } from '../stores/market'
 
 // Simplified bolt11 parser to extract payment hash