Remove unadopted renderer remnants

[VdustR]

Summary

• remove the obsolete third-party renderer cleanup script
• stop install and uninstall flows from invoking that renderer's CLI
• remove related documentation, setup guidance, tests, and CI references

Verification

• PYTHONPATH=src python3 -m unittest discover -s tests -v (72 tests)
• pyright src tests (0 errors)
• python3 -m compileall -q src tests
• swift test --package-path native (9 tests)
• shell syntax validation for build, install, uninstall, and setup scripts
• repository search for the removed product name, acronym, CLI, and environment variable (0 matches)

[changeset-bot]

⚠️ No Changeset found

Latest commit: ba837f9

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[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 2026-09-01T16:35:29.266330Z	ba837f9	Draft marked ready

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