Newline corruption in multi-line secrets (SSH Keys) added via Extension

Multi-line RSA/PEM secrets added via the VS Code extension fail authentication in GitHub Actions. Re-adding the identically pasted content via the GitHub web UI resolves the issue. This suggests the extension may be incorrectly handling or encoding newline characters.

Steps to Reproduce
Copy a valid multi-line PEM SSH key.
In VS Code, navigate to GitHub Actions > Secrets > Add Secret.
Paste the key and save.
Trigger a workflow using the secret (e.g., appleboy/ssh-action).
Expected Behavior
The secret should maintain its original formatting and be valid for SSH authentication.

Actual Behavior
Workflow fails with: ssh: handshake failed: ssh: unable to authenticate, attempted methods [none], no supported methods remain

Workaround
Deleting the secret and re-adding it through the GitHub.com web interface works immediately.

Environment
Extension Version: 0.29.1
OS: Linux (WSL2 / Ubuntu 24.04)

Start by reproducing the problem through VS Code's GitHub Actions > Secrets > Add Secret flow with a multi-line PEM key, then compare the extension's saved secret behavior with the GitHub web UI workaround. Trace the secret-save path and verify that the stored value preserves newline formatting and authenticates successfully in a workflow.

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