Merge pull request 'Use loopback for host builder probes' (#5) from fix/gitea-builder-loopback-20260727 into main

.github/workflows/candidate.yml

@@ -304,9 +304,7 @@ jobs:
           test "$actual_client_sha" = "$EXPECTED_CLIENT_SHA"
           echo "value=$actual_client_sha" >> "$GITHUB_OUTPUT"
       - name: Resolve the private Docker host transport
-        run: |
-          probe_host="$(ruby scripts/private_default_gateway.rb)"
-          echo "OPENCODE_PROBE_HOST=$probe_host" >> "$GITHUB_ENV"
+        run: echo "OPENCODE_PROBE_HOST=127.0.0.1" >> "$GITHUB_ENV"
       - name: Exercise the complete manifest matrix without artifact claims
         env:
           BUNDLE_GEMFILE: ${{ github.workspace }}/ruby-client/Gemfile

test/repository_test.rb

@@ -381,8 +381,7 @@ class RepositoryTest < Minitest::Test
     assert_includes workflow, "exact-image-contract-gitea:"
     assert_includes workflow, "if: github.server_url != 'https://github.com'"
     assert_includes workflow, "run: scripts/run_image_matrix_contract.sh"
-    assert_includes workflow, 'probe_host="$(ruby scripts/private_default_gateway.rb)"'
-    assert_includes workflow, 'echo "OPENCODE_PROBE_HOST=$probe_host" >> "$GITHUB_ENV"'
+    assert_includes workflow, 'echo "OPENCODE_PROBE_HOST=127.0.0.1" >> "$GITHUB_ENV"'
     assert_operator workflow.scan('BUNDLE_GEMFILE: ${{ github.workspace }}/ruby-client/Gemfile').length, :>=, 2
     assert_operator workflow.scan("generated JSON is transient and is not review evidence").length, :>=, 3