Module credentials 

Credential storage for LLM provider API keys.

Provides a trait-based abstraction over credential storage with two implementations:

• KeyringCredentialStore: Uses the OS-native credential store (macOS Keychain, Windows Credential Manager, Linux Secret Service).
• InMemoryCredentialStore: In-memory store for testing.

Structs

InMemoryCredentialStore

In-memory credential store for testing.

KeyringCredentialStore

OS-native credential store using the keyring crate.

Enums

CredentialError

Errors from credential storage operations.

Traits

CredentialStore

Trait for credential storage backends.