Backend/bugs: Use markdown to format GitHub issues

[tristanlabelle]

Adds formatting to GitHub issues for readability.

Testing

Replicated the formatting in a comment to preview it (see pics below). Used gh api --method POST to validate that "body" can contain markdown.

Before:

After:

Backend checklist

• Added tests for any new code or added a regression test if fixing a bug
• Run the backend locally and it works
• Added migrations if there are any database changes, rebased onto develop if necessary for linear migration history

For maintainers

• Maintainers can push commits to my branch
• Maintainers can merge this PR for me

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Project	Deployment	Actions	Updated (UTC)
couchers	Ready	Preview	May 20, 2026 6:02am

[github-actions]

📝 Release Notes

This PR does not need to be included in release notes.

Reason: This change only improves the internal formatting of GitHub bug reports for maintainers reading issues. It does not add or change user-facing functionality, fix an important end-user bug, or represent major technical infrastructure work that users would notice.

🤖 Bot Debug Information

Model: couchers.openai.gpt-5.4
Decision: exclude
Reasoning: This change only improves the internal formatting of GitHub bug reports for maintainers reading issues. It does not add or change user-facing functionality, fix an important end-user bug, or represent major technical infrastructure work that users would notice.