[SYNC] Synchronize payment-terminals module from erp-core canonical

Source: erp-core (checksum: c9040e545cf55beb87d3e437a4998855)
Priority: P1 - HIGH
Context: TASK-2026-01-25-SISTEMA-REUTILIZACION

Before: Diverged version (one of 3 different versions)
After: Synced with canonical

Changes:
- Complete payment-terminals module synchronized from erp-core
- 21 TypeScript files updated
- Unified payment terminal integration (MercadoPago + Clip)
- Consistent webhook handling across all ERP projects

Benefits:
- Single source of truth for payment terminals functionality
- Consistent TPV integration behavior
- Reduced maintenance burden (~4,000 lines saved)
- Unified webhook processing

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/modules/payment-terminals/payment-terminals.module.ts

@@ -62,6 +62,10 @@ export class PaymentTerminalsModule {
    */
   static getEntities() {
     return [
+      // Existing entities
+      require('../branches/entities/branch-payment-terminal.entity').BranchPaymentTerminal,
+      require('../mobile/entities/payment-transaction.entity').PaymentTransaction,
+      // New entities for MercadoPago/Clip
       require('./entities/tenant-terminal-config.entity').TenantTerminalConfig,
       require('./entities/terminal-payment.entity').TerminalPayment,
       require('./entities/terminal-webhook-event.entity').TerminalWebhookEvent,