fix(docker): always pull the latest PHP 8.4 base image on release builds

Picks up PHP 8.4.27 for CVE-2026-109618 and CVE-2026-109619 (critical RCE)
via the floating 1-php8.4-alpine tag.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/docker-publish.yml

@@ -77,6 +77,7 @@ jobs:
           target: final
           platforms: linux/amd64,linux/arm64
           push: true
+          pull: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           # Registry-based layer cache — survives between runs without a separate cache store.