Show HN: Fix Gate – verifies security-fix PRs, incl. AI-written ones

Fix Gate is a free GitHub Action that verifies security-fix pull requests, including output from Copilot Autofix, Snyk Agent Fix or a person, by running Railo's rules over the base and head versions of changed files and posting five checks as a check run. It reports whether the targeted finding is gone, whether new findings appeared in the changed lines, whether changed files still parse, whether tests newly failed, and whether an added validator rejects a fixed list of known bypass payloads. The engine is not open source, runs only on pull_request events, and the guard row executes the pull request's validator function in a separate unprivileged subprocess rather than a container boundary.