[WinUI OSS] Evaluate repository bots and slash commands

@niels9001 is already working on this.

Since Aug 25, 2026.

## Summary

Investigate which GitHub bots, slash commands, or automation helpers would improve WinUI triage, labeling, stale-item handling, and contributor experience.

## Context

As more tracking and development moves into GitHub, maintainers may need lightweight automation for common repository actions. Good automation should reduce manual triage work without making the public contributor experience confusing or opaque.

This issue should evaluate public GitHub-facing behavior and avoid private service details, internal automation endpoints, or hidden command semantics.

## Work to do

- Identify repetitive maintainer workflows that could benefit from bots or slash commands.
- Review existing GitHub-native options and patterns used by comparable public repositories.
- Decide which actions should be automated, which should remain manual, and which require policy discussion.
- Define expected public behavior for labels, stale issue handling, triage routing, and contributor notifications.
- Track implementation tasks separately once the desired automation is clear.

## Definition of done

- Candidate bots or slash commands are documented with expected public behavior.
- Automation risks and contributor-experience concerns are understood.
- Implementation follow-ups are created for approved automation.
- Public issue content avoids private endpoints, tokens, hidden commands, or internal service names.