docs: replace deprecated #workspace with #codebase in Understanding Copilot Context

[Copilot]

#workspace has been removed from GitHub Copilot Chat and replaced by #codebase. The Learning Hub doc "Understanding Copilot Context" still referenced #workspace in its Common Questions section.

Changes

• website/src/content/docs/learning-hub/understanding-copilot-context.md: Updated the answer to "How do I know what context Copilot is using?" — replaced `#workspace` with `#codebase` as the chat variable for searching across the entire repository.

Pull Request Checklist

• I have read and followed the CONTRIBUTING.md guidelines.
• I have read and followed the Guidance for submissions involving paid services.
• My contribution adds a new instruction, prompt, agent, skill, or workflow file in the correct directory.
• The file follows the required naming convention.
• The content is clearly structured and follows the example format.
• I have tested my instructions, prompt, agent, skill, or workflow with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.
• I am targeting the staged branch for this pull request.

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Description

#workspace no longer exists in GitHub Copilot Chat; #codebase is the current replacement. One sentence in the Learning Hub referenced the removed variable.

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Type of Contribution

• New instruction file.
• New prompt file.
• New agent file.
• New plugin.
• New skill file.
• New agentic workflow.
• Update to existing instruction, prompt, agent, plugin, skill, or workflow.
• Other (please specify):

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Additional Notes

See community discussion #102854 for confirmation that #workspace was removed in favour of #codebase.

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By submitting this pull request, I confirm that my contribution abides by the Code of Conduct and will be licensed under the MIT License.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• telemetry.astro.build
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node node /home/REDACTED/work/awesome-copilot/awesome-copilot/website/node_modules/.bin/astro build (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

[Copilot]

Pull request overview

Updates Learning Hub documentation to reflect the current GitHub Copilot Chat context variable, replacing the deprecated #workspace reference with #codebase in “Understanding Copilot Context”.

Changes:

• Replaced #workspace with #codebase in the “How do I know what context Copilot is using?” answer.