sherpa-onnx 1.13.7 wheels require sherpa-onnx-core, which ships
libonnxruntime.so, but the armv7l wheels omit that metadata and uv.lock
recorded no dependency. install.sh installs the export with --no-deps, so
sherpa_onnx failed to import, Settings hid Parakeet and the installer
quietly switched config.json to whisper.cpp while still reporting Parakeet.
List sherpa-onnx-core in the parakeet extra, verify engine imports right
after installing them, and keep SELECTED_ENGINE in sync when the config
is repaired so the summary names the engine actually configured.
Fixes#973