- 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>