[process] Update the triaging process (and doc)

The triaging doc is out of date and it would be great to modernize it.

As we do, it would be nice to consider what bits of process can be shared across other devexp teams (to facilitate/anticipate shared rotations).

- [x] Task 0: Update Untriaged/Inbox Query
- [x] https://github.com/flutter/flutter-intellij/pull/8246
- [x] Task 1: Add @pq to the Triage rotation (internal)
- [x] Task 2: update triage email text (internal)
- [ ] Task 3: Consider a triage dashboard/weekly report

### References

https://github.com/flutter/flutter/wiki/2025-Issue-Triage-Reports
https://github.com/microsoft/vscode/wiki/Issues-Triaging

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/fyi @jwren @kenzieschmoll