chore(issue-triage): scope refresh to issue-triage; drop unrelated maintenance workflow

The setup PR (cli#13777) meaningfully updated only the issue-triage
workflow, so this refresh must touch issue-triage alone. gh-aw v0.83.0
otherwise auto-generates a repo-wide agentics-maintenance.yml companion
workflow, which is out of scope here.

Suppress that generation with the documented compiler toggle
`.github/workflows/aw.json` {"maintenance": false} and remove the
previously generated agentics-maintenance.yml. No repo variables changed
and no safe-output tools added.

issue-triage is unaffected: its lock, the issue-intent enablement on
add-labels, and the v0.83.0 toolchain bump are all preserved.

Validated with `gh aw compile` (v0.83.0) and `gh aw validate`
(0 errors, 0 warnings); idempotent on re-compile (maintenance workflow
does not regenerate).

Refs github/plan-track-agentic-toolkit#519

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 628d4172-49f6-4d5c-905c-a33276de3aee

Author: alondahari