docs(triage): add triage duty tooling

[elezar]

Summary

Add the triage-duty queue review and user-gated action workflows, including a
local playbook and explicit continuation order for in-progress triage passes.

Related Issue

No issue required: triage-process tooling and documentation. Replaces #2978 and #3081.

Changes

• Add read-only queue review and user-gated recommendation-application skills.
• Surface open Dependabot pull requests before general community pull requests.
• Keep triage-duty local state and inbox out of version control.
• Preserve report-local order when resuming a triage pass; record the next issue
  in the checkpoint.

Testing

• git diff --check origin/main...HEAD
• mise run pre-commit (not run: mise is unavailable in this environment)
• Unit tests added/updated (documentation and skill workflow changes only)
• E2E tests added/updated (not applicable)

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)