fix(release): drop the dead OMP adapter verification step

The step ran node tests/omp/omp-plugin.test.js, which has never existed in
this repository. It was added by #2382 without the test file, so Verify
Release failed on every tag and no release could publish.

The OpenCode payload is already verified by tests/scripts/build-opencode.test.js
in the preceding step, and the plugin and marketplace manifests by
tests/plugin-manifest.test.js in Verify release metadata stays in sync.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0149VwNuynam6rvEfcMmiHHa

.github/workflows/release.yml

@@ -38,9 +38,6 @@ jobs:
       - name: Verify OpenCode package payload
         run: node tests/scripts/build-opencode.test.js
 
-      - name: Verify OMP adapter payload
-        run: node tests/omp/omp-plugin.test.js
-
       - name: Validate version tag
         run: |
           if ! [[ "${REF_NAME}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.-]+)?$ ]]; then