fix(docker-build): scope packages: write to the pushing jobs

.github/workflows/docker-build.yml

@@ -93,13 +93,16 @@ on:
       DOCKERHUB_TOKEN:
         description: "Docker Hub token for dhi.io base images and docker.io pushes; only read when configured"
 
+# Read-only by default; each job that pushes to GHCR asks for `packages: write` itself.
 permissions:
   contents: read
-  packages: write
 
 jobs:
   build:
     name: Build ${{ matrix.platform.platform }}
+    permissions:
+      contents: read
+      packages: write
     strategy:
       fail-fast: true
       matrix:
@@ -243,6 +246,9 @@ jobs:
   merge:
     name: Publish multi-arch manifests
     needs: build
+    permissions:
+      contents: read
+      packages: write
     runs-on: ubuntu-24.04
     timeout-minutes: 15
     steps:

tests/test_docker_build.py

@@ -17,6 +17,15 @@ class DockerBuildWorkflowTests(unittest.TestCase):
         self.assertIn("DOCKERHUB_TOKEN", call["secrets"])
         self.assertNotIn("DIGITALOCEAN_TOKEN", call["secrets"])
 
+    def test_write_permission_is_job_scoped(self):
+        """Only the pushing jobs get `packages: write` (SonarCloud githubactions:S8233)."""
+        self.assertEqual(WORKFLOW["permissions"], {"contents": "read"})
+        for job in ("build", "merge"):
+            self.assertEqual(
+                WORKFLOW["jobs"][job]["permissions"],
+                {"contents": "read", "packages": "write"},
+            )
+
     def test_dockerhub_login_in_build_job(self):
         steps = WORKFLOW["jobs"]["build"]["steps"]
         dh_step = next(