ci/task-board: use runner default image (node:20-bookworm-slim)

debian:bookworm-slim lacks node, so actions/checkout@v4 (a JS action
running dist/index.js) fails with `exec: "node": executable file not
found in $PATH`. Dropping the explicit `container:` directive lets
the runner use its label-default — node:20-bookworm-slim has node +
git out of the box. Install step shrinks to python3 + pyyaml +
openssh-client.

stacks/task-board/gitea-workflow-deploy.yaml.example

@@ -36,20 +36,18 @@ jobs:
   deploy:
     # `pfi-fleet` matches the central runner on ana-docker. Pin to
     # `ana-docker` instead if you want to refuse running on a future
-    # site-local runner.
+    # site-local runner. The runner's label embeds a default image
+    # (node:20-bookworm-slim) — has node + git out of the box, so
+    # actions/checkout@v4 (a JS action) works without a custom
+    # container. We just apt-install python3 + pyyaml for elway.
     runs-on: pfi-fleet
 
-    # Debian image picked because the elway playbook uses python3 +
-    # pyyaml (Debian package: python3-yaml). Keeps the install step short.
-    container:
-      image: debian:bookworm-slim
-
     steps:
       - name: Install playbook prerequisites
         run: |
           apt-get update -qq
           apt-get install -y --no-install-recommends \
-            python3 python3-yaml openssh-client ca-certificates curl git
+            python3 python3-yaml openssh-client
           rm -rf /var/lib/apt/lists/*
 
       - name: Checkout task-board (triggering repo)