feat(sat): add database models for SAT sync

Phase 1 - Database models:
- Add FielCredential model for encrypted FIEL storage
- Add SatSyncJob model for sync job tracking
- Add SAT-related enums (SatSyncType, SatSyncStatus, CfdiSyncType)
- Add TypeScript types in shared package
- Relations: Tenant -> FielCredential (1:1), Tenant -> SatSyncJobs (1:N)

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

packages/shared/src/index.ts

@@ -8,6 +8,7 @@ export * from './types/impuestos';
 export * from './types/alertas';
 export * from './types/reportes';
 export * from './types/calendario';
+export * from './types/sat';
 
 // Constants
 export * from './constants/plans';