Fix: Add CLAUDE_CREDENTIALS env var back to prepare step

The prepare step needs access to the credentials to extract the OAuth token

action.yml

@@ -109,6 +109,7 @@ runs:
         GITEA_API_URL: ${{ env.GITHUB_SERVER_URL }}
         # Only set ANTHROPIC_API_KEY if not using OAuth
         ANTHROPIC_API_KEY: ${{ inputs.anthropic_api_key != 'use-oauth' && inputs.anthropic_api_key || '' }}
+        CLAUDE_CREDENTIALS: ${{ inputs.claude_credentials }}
 
     - name: Run Claude Code
       id: claude-code