- Add Ping method to PostgresProfileStore to check database connection status
- Add Ping method to ProfileRepository interface
- Add /api/v1/health/live endpoint for liveness checks (always returns alive if service is running)
- Add /api/v1/health/ready endpoint for readiness checks with database connectivity validation
- Add readinessHandler that returns SERVICE_UNAVAILABLE status when database ping fails
- Add profileRow struct with ICCID/EID/IMSI/MCC/MNC/ProfileType/State/TenantID/ActivationCode/CreatedAt/UpdatedAt fields mapped to esim_profiles table with indexes on EID/IMSI/State/TenantID
- Add NewPostgresProfileStore with DSN validation, GORM connection setup with Warn logging, and AutoMigrate for esim_profiles schema
- Add Create/Get/List/UpdateState/Delete methods implementing ProfileRepository interface with