Establish triage cadence for issues and PRs

[IanoNjuguna]

Problem

Implement a defined process for how often issues and PRs are triaged, by whom, or what happens to inactive items. Contributors have no visibility into response-time expectations beyond the 48-hour PR review mentioned in CONTRIBUTING.md

Proposal

Establish and document a triage cadence:

• Add TRIAGE.md defining triage frequency (weekly, aligned with DevEx working-group sessions), labels, SLAs, and stale-item policy
• Add a stale-bot workflow (.github/workflows/stale.yml) to automate the inactivity policy
• Link the TRIAGE.md in the CONTRIBUTING.md

STATUS: in progress

[IanoNjuguna]

STATUS: awaiting merge