Issues/1449 - Improve Linux Keyring Support with Keyctl Fallback

[mauriciocoder]

Overview

This PR enhances the keyring system to provide support for headless Linux environments by implementing a composite keyring provider with keyctl as a fallback backend.

Key Changes

🔧 New Composite Keyring Architecture

• Introduced a new Provider interface for pluggable keyring backends
• Implemented a composite provider that automatically selects the best available backend
• Maintains full backward compatibility with existing keyring functionality

🐧 Linux Keyctl Support

• Added keyctl provider as a fallback for Linux systems where D-Bus Secret Service is unavailable
• Particularly beneficial for headless Linux environments, containers, and minimal installations

🧪 Comprehensive Testing

• Added full test coverage for all new keyring providers

Resolves #1449