fix: remove broken plugin marketplace auth from code review workflow

The plugin_marketplaces + plugins config triggered an OIDC token exchange
that consistently fails with 401. Replace with a direct prompt, matching
the pattern used in claude.yml which works reliably.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/claude-code-review.yml

@@ -24,6 +24,7 @@ jobs:
         uses: anthropics/claude-code-action@v1
         with:
           claude_code_oauth_token: ${{ secrets.CLAUDE_CODE_OAUTH_TOKEN }}
-          plugin_marketplaces: 'https://github.com/anthropics/claude-code.git'
-          plugins: 'code-review@claude-code-plugins'
-          prompt: '/code-review:code-review ${{ github.repository }}/pull/${{ github.event.pull_request.number }}'
+          prompt: >
+            Review this pull request for bugs, logic errors, security issues, and adherence to project
+            conventions. Focus only on high-confidence issues that genuinely matter. Skip style nitpicks.
+            Post your findings as inline review comments on the relevant lines.