test(plugin): accept a detached MCP payload

[soyeon-oai]

Summary

Allow MCP runtime and smoke tests to validate a detached, materialized plugin payload instead of requiring the SDK-local generated payload path.

Changes

• accept CODEX_SECURITY_TEST_PLUGIN_ROOT as the complete plugin payload used for shipped-runtime and end-to-end smoke assertions
• preserve the existing SDK _bundled_plugin path as the default

Testing

• confirmed the test fails when the generated SDK payload is absent before this change
• built a complete plugin into a temporary directory with buildBundledPlugin
• ran the complete test:mcp suite with CODEX_SECURITY_TEST_PLUGIN_ROOT set to that temporary plugin

Risk and rollout

Low risk. Production plugin behavior is unchanged. Existing SDK test callers retain the same default; alternate plugin materializers can opt into the override.

Public disclosure review

• No customer, partner, prospect, or user identities, data, or identifying details are included.
• No credentials, personal data, private source, scan findings, or nonpublic links or tickets are included.
• I reviewed the branch name, title, description, commits, changes, comments, logs, screenshots, attachments, and links for public disclosure.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-08-27T21:37:06.662137Z	a6d8a7a	PR opened
🔒 Security Review	✅ Completed 2026-08-27T21:37:15.540080Z	a6d8a7a	PR opened

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