lint-monster: skip-if recent open issues (24h), single agent session

[Copilot]

lint-monster runs daily and was launching up to 3 Copilot agent sessions per run with no guard against duplicate work when agents from a previous run are still active.

Changes

• Skip-if recent issues (24h): Added a gh search issues check at the start of the pre-check step. If any open [lint-monster] issues exist with created:>=<yesterday>, sets lint-clean.flag → agent calls noop.

CUTOFF=$(date -u -d '24 hours ago' '+%Y-%m-%d')
RECENT=$(gh search issues \
  --repo "$GH_AW_GITHUB_REPOSITORY" \
  --state open \
  --json number \
  -- "in:title \"[lint-monster]\" created:>=${CUTOFF}" \
  | jq 'length')
if [ "${RECENT:-0}" -gt 0 ]; then
  touch /tmp/gh-aw/agent/lint-clean.flag
  exit 0
fi

• Single agent session: assign-to-agent: max and create-issue: max reduced from 3 → 1. Agent instructions updated to select only the group with the most findings per run rather than dispatching up to three parallel groups.

Lock file recompiled; ${{ github.repository }} automatically extracted to $GH_AW_GITHUB_REPOSITORY by the compiler for injection safety.