Introduces a new cryptographic key management system for user sessions, including models, DTOs, interfaces, and services for handling identity keys, signed pre-keys, and one-time pre-keys. Updates the SessionKeysController and DI configuration to use the new services. Adds related EF Core configurations and migrations, and updates the UserSession model to reference the new UserCryptoSession. Removes the obsolete ISessionKeyService interface.
The JwtService now includes sessionId in access tokens, and all usages have been updated to pass sessionId when generating tokens. UserSession now supports public encryption and signing keys. Tests and session management logic have been updated to reflect these changes, ensuring session-specific claims in JWTs and improved session tracking.