[Feature][gh-copilot] Support GitHub App authentication (in addition to PAT)

[fool65c]

Search before asking

• I had searched in the issues and found no similar feature requirement.

Use case

As an engineer, I would like to connect DevLake to GitHub Copilot usage & impact data using a GitHub App installation so that:

• We avoid storing user-owned PATs
• Access is least-privilege, centrally managed, and revocable
• The integration is not tied to a specific employee account
• It aligns with enterprise security and compliance requirements

Description

Add support for GitHub App authentication to the GitHub Copilot plugin. Specifically, allow Copilot data collection to authenticate using:

• GitHub App ID
• Installation ID
• Private key (PEM / secret reference)

The plugin should:

• Allow users to configure both PAT and App authentication via the UI
• Generate GitHub App installation access tokens
• Automatically refresh tokens during collection
• Support scheduled and long-running pipelines without token expiration failures

Existing PAT-based authentication should continue to work unchanged.

Related issues

No response

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[klesh]

Sounds great. I believe it would a good addition to the plugin.
cc @ewega