Reject marketplace publisher routes

[kriptoburak]

Summary

• Reject marketplace publisher extensions and external-PR-closing plugin marketplaces without a PR-editable source catalog lane.
• Reject live catalog MCP wrappers that only expose another catalog without a third-party source entry.
• Add route-rejection fixture coverage for the new cases.

Validation

• uv run --python 3.12 --extra dev pytest tests/test_submission_readiness.py
• uv run --python 3.12 --extra dev ruff format --check
• uv run --python 3.12 --extra dev ruff check
• uv run --python 3.12 --extra dev python scripts/check_public_safety.py
• uv run --python 3.12 --extra dev pytest tests/test_public_safety.py
• uv run --python 3.12 --extra dev pip-audit
• uv run --python 3.12 --extra dev python scripts/check_public_links.py
• git diff --check

Note

Add marketplace publisher route rejection phrases to submission readiness criteria

Extends SUBMISSION_READINESS.md and the safety_duplicates.txt fixture with new rejection phrases covering VS Code Copilot marketplace publisher extensions, external-PR-closing plugin marketplaces, publication tooling, external submission forms, member-only contribution lanes, and live catalog MCP wrappers. Any logic or tests consuming the fixture will now apply these additional phrases when evaluating routes for rejection.

^{Macroscope summarized fe93b07.}