Completion Tracking Without an Installed Claude CLI

The post-merge completion tracker asks the Claude CLI for a semantic verdict. That check is intentionally non-blocking, but the tracker still crashed when it ran on a GitHub Actions runner where the optional claude binary was not installed.

The tracker now treats a missing Claude executable like any other unavailable verdict input and returns None. The lifecycle nudge can continue, and a later scan can retry when the environment provides the dependency.

A regression test monkeypatches subprocess.run to raise FileNotFoundError for the Claude invocation and verifies that the tracker fails soft instead of propagating the exception.