ci: pull ci-runner-go from zot registry

.gitea/workflows/ci.yml

@@ -70,7 +70,11 @@ jobs:
     # one runner. The third shard ("rest") covers everything else.
     name: Test (${{ matrix.name }})
     runs-on: ubuntu-latest
-    container: gitea.dcglab.co.uk/steve/ci-runner-go:2026-05-08
+    container:
+      image: docker.dcglab.co.uk/ci-runner-go:2026-05-15
+      credentials:
+        username: ${{ secrets.ZOT_USERNAME }}
+        password: ${{ secrets.ZOT_PASSWORD }}
     strategy:
       fail-fast: false
       matrix:
@@ -105,7 +109,11 @@ jobs:
   lint:
     name: Lint
     runs-on: ubuntu-latest
-    container: gitea.dcglab.co.uk/steve/ci-runner-go:2026-05-08
+    container:
+      image: docker.dcglab.co.uk/ci-runner-go:2026-05-15
+      credentials:
+        username: ${{ secrets.ZOT_USERNAME }}
+        password: ${{ secrets.ZOT_PASSWORD }}
     steps:
       - uses: actions/checkout@v4
       - uses: golangci/golangci-lint-action@v7
@@ -121,7 +129,11 @@ jobs:
   build:
     name: Build (${{ matrix.goos }}/${{ matrix.goarch }})
     runs-on: ubuntu-latest
-    container: gitea.dcglab.co.uk/steve/ci-runner-go:2026-05-08
+    container:
+      image: docker.dcglab.co.uk/ci-runner-go:2026-05-15
+      credentials:
+        username: ${{ secrets.ZOT_USERNAME }}
+        password: ${{ secrets.ZOT_PASSWORD }}
     strategy:
       fail-fast: false
       matrix: