[DX-1080] Setup GitHub Copilot for private dependencies

[goflink-platform-argo-workflows]

🚀 GitHub Copilot Setup for Private Dependencies

This PR adds the GitHub Copilot setup workflow to enable automated dependency resolution for private GoFlink repositories.

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What's Included?

✅ .github/workflows/copilot-setup-steps.yml - Workflow that configures Copilot for Go private dependencies
✅ COPILOT_PRIVATE_SSH_KEY secret added to copilot environment
ℹ️ No private GoFlink dependencies found in go.mod

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Private Dependencies Found

No private GoFlink dependencies detected.

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✅ Copilot Bot Access Granted

No repository access was granted (no private dependencies found or all access grants failed).

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How It Works

1. The workflow triggers on:

   • Manual workflow dispatch
   • Pull requests modifying the workflow file
   • Copilot session starts in the repository

2. Uses the copilot-setup-go GitHub Action to:

   • Enable Copilot to fetch private GoFlink dependencies for sessions

3. The Copilot bot user has read-only access to dependency repositories for Copilot to be able to fetch them.

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Testing the Setup

After merging this PR, GitHub Copilot will automatically have access to your private dependencies. You can verify this by:

1. The workflow will run on PR creation to validate the setup
2. After the PR is merged, start a Copilot session in the repository and check if private dependencies are resolved correctly.

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❓ Got questions?
Reach out to #ask-platform for assistance.

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🤖 This PR was generated by Temporal Workflow.