Adding logic to render external plugins with canvases in the canvas gallery

[aaronpowell]

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, workflow, or canvas extension 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, workflow, or canvas extension with GitHub Copilot.
• I have run npm start and verified that README.md is up to date.
• I am targeting the main branch for this pull request.

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Description

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Type of Contribution

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

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Additional Notes

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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.

[Copilot]

Pull request overview

Adds external canvas plugins to the website’s canvas gallery.

Changes:

• Reads validated external plugin metadata.
• Generates gallery entries, preview URLs, source links, and filters.
• Deduplicates external entries against existing extensions.

Show a summary per file

File	Description
eng/generate-website-data.mjs	Adds external canvas discovery and manifest generation.

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 3
• Review effort level: Medium

[Copilot]

Review details

• Files reviewed: 1/1 changed files
• Comments generated: 2
• Review effort level: Medium

[Copilot]

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 2
• Review effort level: Medium