Github Copilot provider not working

Description

When attempting to add GitHub Copilot as an AI provider and testing the model connection, the application fails to recognize GitHub Copilot as a valid provider.

This was just implemented but i guess not tested. #394

Error Message

Model test failed: CompletionError: ProviderError: unknown provider: github-copilot

Steps to Reproduce

1. Navigate to the provider settings in Spacebot to add a new API key.
2. Select GitHub Copilot as the provider.
3. Enter a valid GitHub Copilot API key.
4. Input the model ID: github-copilot/claude-sonnet-4
5. Click Test model.
6. See the error displayed in the UI.

Expected Behavior

The system should successfully verify the API key and model against the GitHub Copilot API, and save the configuration without throwing an "unknown provider" error.

Actual Behavior

The test fails immediately with a CompletionError stating that github-copilot is an unknown provider.

Environment

• Spacebot Version: v0.3.3
• OS: Docker (Linux)

Screenshots

Start by reproducing the failure from Spacebot's provider settings: select GitHub Copilot, enter the documented model ID, and run Test model. Trace the provider lookup that produces the unknown provider: github-copilot error and compare it with the implementation referenced by issue #394. Done means a valid Copilot configuration is recognized, tested successfully, and saved without that error.