feat(saas): update schema for db-per-tenant and per-component FIEL encryption

- Rename Tenant.schemaName to databaseName across all services
- Add Subscription and Payment models to Prisma schema
- Update FielCredential to per-component IV/tag encryption columns
- Switch FIEL encryption key from JWT_SECRET to FIEL_ENCRYPTION_KEY
- Add Subscription and Payment shared types
- Update JWTPayload to use databaseName

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/shared/src/types/auth.ts

@@ -36,7 +36,7 @@ export interface JWTPayload {
   email: string;
   role: Role;
   tenantId: string;
-  schemaName: string;
+  databaseName: string;
   iat?: number;
   exp?: number;
 }

packages/shared/src/types/tenant.ts

@@ -5,7 +5,7 @@ export interface Tenant {
   nombre: string;
   rfc: string;
   plan: Plan;
-  schemaName: string;
+  databaseName: string;
   cfdiLimit: number;
   usersLimit: number;
   active: boolean;
@@ -20,3 +20,29 @@ export interface TenantUsage {
   usersLimit: number;
   plan: Plan;
 }
+
+export interface Subscription {
+  id: string;
+  tenantId: string;
+  plan: Plan;
+  mpPreapprovalId?: string;
+  status: 'pending' | 'authorized' | 'paused' | 'cancelled';
+  amount: number;
+  frequency: 'monthly' | 'yearly';
+  currentPeriodStart?: string;
+  currentPeriodEnd?: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
+export interface Payment {
+  id: string;
+  tenantId: string;
+  subscriptionId?: string;
+  mpPaymentId?: string;
+  amount: number;
+  status: 'approved' | 'pending' | 'rejected' | 'refunded';
+  paymentMethod?: string;
+  paidAt?: string;
+  createdAt: string;
+}