feat: ssh key retention

[dcoric]

This pull request introduces a comprehensive SSH key retention feature for Git Proxy, enabling secure storage and reuse of user SSH keys during the approval process. This eliminates the need for re-authentication after push approval, while maintaining robust security measures such as encryption, expiration, and cleanup. The changes span documentation updates, new components, database schema modifications, and enhancements to existing processing flows.

Documentation and Architecture Updates:

• docs/SSH_KEY_RETENTION.md: Added detailed documentation covering the problem statement, solution architecture, security features, implementation details, configuration, and future enhancements for the SSH key retention feature.

Core Feature Implementation:

• src/security/SSHAgent.ts: Introduced the SSHAgent class to securely manage SSH keys in memory, with features such as automatic expiration, secure cleanup, and signing capabilities.
• src/proxy/processors/push-action/captureSSHKey.ts: Added a processor to capture and store SSH key information during push processing when approval is required.

Database and Action Enhancements:

• src/db/types.ts: Extended the Push type to include fields for encrypted SSH keys, expiration timestamps, and protocol information.
• src/proxy/actions/Action.ts: Updated the Action class to support SSH user information, including public key details and protocol-specific data.

Processing Flow Updates:

• src/proxy/chain.ts: Integrated the new captureSSHKey processor into the push action chain to ensure SSH key capture before processing.
• src/proxy/processors/pre-processor/parseAction.ts: Enhanced the pre-processor to set protocol and SSH user information for SSH-based pushes. [1] [2]Storing user key for post-approval process

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None