Improve the transparency of triage, ownership, and public decision-making process in the WASDK and WinUI repos

[0x5bfa]

It would be helpful to more clearly document how issues, pull requests, and proposals are handled in the Windows App SDK and WinUI repositories.

What's the issue

Currently, it can be difficult for contributors to understand:

• Whether the responsible team has seen an issue
• What needs-triage means after an area label is added
• Which team owns a particular area
• When and how to request additional attention
• Where review decisions are documented

Proposal

Possible improvements could include:

• Documenting the current triage and ownership process
• Explaining the meaning and lifecycle of labels
• Listing GitHub teams or aliases for major areas instead of individual developers
• Adding a label such as needs-area-owner-attention
• Holding occasional public or recorded review meetings
• Posting meeting notes, review outcomes, and recording timestamps back to the related GitHub issues

The goal is to make GitHub a clearer source of truth and help contributors understand the status and next steps for their issues and pull requests.

Additional context

The .NET repositories provide some useful examples, such as public area-owner documentation and streamed API reviews with outcomes posted back to GitHub.

• A documented area-owners.md: https://github.com/dotnet/runtime/blob/main/docs/area-owners.md
• An automated assign system by the .NET runtime team
• An open and transparent viewer for reviews: https://apireview.net/

CC Roy (@RDMacLachlan)