Add a human-merge label that keeps autopilot from merging

autopilot skips both human checkpoints: approval before the build and the
merge. Scheduled update issues in homelab want the hands-off build but a human
merge, since merging there deploys. With human-merge also on the issue, @pm is
told to hand back at phase 3 and publish.sh refuses MERGE_PR.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.gitea/workflows/agent.yml

@@ -268,6 +268,7 @@ jobs:
           HAS_IMAGES: ${{ steps.imgs.outputs.has_images }}
           BRANCH: ${{ steps.prep.outputs.branch }}
           AUTOPILOT: ${{ steps.prep.outputs.autopilot }}   # 'true' when the issue carries the `autopilot` label
+          AUTOMERGE: ${{ steps.prep.outputs.automerge }}   # 'false' when `human-merge` is also set
           NUM: ${{ github.event.issue.number }}
           TITLE: ${{ github.event.issue.title }}
           IBODY: ${{ github.event.issue.body }}
@@ -305,6 +306,7 @@ jobs:
           NEW: ${{ steps.prep.outputs.new }}
           IS_PR: ${{ github.event.issue.pull_request }}   # set when this run is on a PR thread
           AUTOPILOT: ${{ steps.prep.outputs.autopilot }}   # 'true' when the origin issue carries `autopilot`
+          AUTOMERGE: ${{ steps.prep.outputs.automerge }}   # 'false' when `human-merge` is also set
           ISSNUM: ${{ steps.prep.outputs.issnum }}          # origin issue number (resolved from branch on PR threads)
         run: bash "$SCRIPTS/publish.sh"