Show HN: RealDiff – runtime behavior diffing for pull requests (six languages)

RealDiff instruments both branches of a pull request, runs the existing test suite on each, and compares recorded method arguments and return values to reveal runtime behavior changes that source diffs miss. It highlights the first divergent behavior, filters out self-noise such as timestamps or GUIDs, and requires only Git, .NET 8 SDK, and PowerShell 7.