Add new collection

[filmgirl]

New collection for winners from the GitHub Copilot SDK contest on Reddit

Please confirm this pull request meets the following requirements:

• I followed the contributing guidelines: https://github.com/github/explore/blob/main/CONTRIBUTING.md.
• This change is not self-promotion.

Which change are you proposing?

• Suggesting edits to an existing topic or collection
• [x ] Curating a new topic or collection
• Something that does not neatly fit into the binary options above

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Editing an existing topic or collection

I'm suggesting these edits to an existing topic or collection:

• Image (and my file is *.png, square, dimensions 288x288, size <= 75 kB)
• Content (and my changes are in index.md)

Please replace this line with an explanation of why you think these changes should be made.

Curating a new topic or collection

• [ x] I've formatted my changes as a new folder directory, named for the topic or collection as it appears in the URL on GitHub (e.g. https://github.com/topics/[NAME] or https://github.com/collections/[NAME])
• [x ] My folder contains a *.png image (if applicable) and index.md
• [x ] All required fields in my index.md conform to the Style Guide and API docs: https://github.com/github/explore/tree/main/docs

A place to showcase the winners of our Copilot SDK reddit contest

Something that does not neatly fit into the binary options above

• My suggested edits are not about an existing topic or collection, or at least not a single one
• My suggested edits are not about curating a new topic or collection, or at least not a single one
• My suggested edits conform to the Style Guide and API docs: https://github.com/github/explore/tree/main/docs

Please replace this line with an explanation of your proposed changes.

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Please note: we will close your PR without comment if you do not check the boxes above and provide ALL requested information.

[Copilot]

Pull request overview

This PR adds a new collection showcasing winners from the GitHub Copilot SDK contest held on Reddit. The collection includes 10 winning projects from the weekend contest.

Changes:

• Creates a new collection directory for GitHub Copilot SDK contest winners
• Adds index.md with metadata and repository links for 10 winning projects
• Includes a 288x288 PNG image (copilot-sdk.png) as required for collections

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated 1 comment.

File	Description
collections/github-copilot-sdk-contest-winners/index.md	Collection metadata with YAML frontmatter, list of 10 winning repositories, display name, creator, and description
collections/github-copilot-sdk-contest-winners/copilot-sdk.png	Collection image file (288x288 PNG format as required)

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[Copilot]

The indentation for the items list uses 1 space, but other collections in this repository use 2 spaces for YAML list indentation (e.g., collections/github-accelerator-2023/index.md and collections/github-browser-extensions/index.md). Please update the indentation to be consistent with the codebase convention by using 2 spaces instead of 1.

[filmgirl]

@copilot open a new pull request to apply changes based on this feedback

[Copilot]

@filmgirl I've opened a new pull request, #5023, to work on those changes. Once the pull request is ready, I'll request review from you.

[ahpook]

Tests passing now 👍