- Add os import for environment variable access
- Update getOperatorVariant to read OP from OPERATOR_VARIANT env var
- Add fallback to default "TelecomOP1234567" for development
- Add zero-padding for OP values shorter than 16 bytes
- Update comments to reference environment variable configuration
- Replace XOR-based OPc generation with AES-128 ECB encryption
- Add getOperatorVariant for consistent OP across subscribers
- Add AES cipher block creation with error handling
- Add OP length validation for AES-128 block size
- Update generateOPc to use crypto/aes for 3GPP-compliant OPc derivation
- Add hardcoded OP placeholder with production configuration note
- Add AMFClient and ES2Service dependencies to SubscriberService
- Initialize AMF client with default URL and ES2 service in NewSubscriberService
- Implement provisionESIMProfile with EID validation, profile provisioning, activation, and AMF notification
- Implement deactivateESIMProfile with profile deactivation, status updates, and session termination
- Add generateOPc helper for deriving OPc from OP and K using XOR-based
- Add SubscriberService struct with Database and Config dependencies
- Add NewSubscriberService constructor
- Add CreateSubscriber with IMSI allocation, auth key generation, and eSIM provisioning support
- Add GetSubscriber and GetSubscriberByIMSI for subscriber retrieval
- Add UpdateSubscriber for subscriber information updates
- Add SuspendSubscriber with session termination
- Add TerminateSubscriber with session termination and eSIM profile deactivation
- Add ListSubscribers with pagination and
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