The test run synthesises a spoken sentence to probe an STT model with real audio
rather than a reachability check. espeak was never in the image, so the probe
fell back to "configured, not verified" — correct behaviour (the gap is ours,
not the model's) and therefore invisible: no error, no failing test. Found by
inspecting a built image.

Added to the full build and to the thin update layer, so it is present whichever
path produced the running image.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0182DhR1eFNPQyGmDrpHbedY