* fix(settings): stop Test Dictation calling a missing model "no speech"
start_recognition now returns whether listening actually began. Test
Dictation checks that before starting its timer, so a missing or
auto-paused model gets a real error instead of "No speech detected".
* fix(settings): reconfigure Test Dictation against the live engine
UI matching config.json is not enough when speech_engine is still on
another engine or model size. Compare those too before the listen timer.
* fix(tests): keep settings_dialog lookups on one module
_load_settings_dialog() restored sys.modules but left
vocalinux.ui.settings_dialog pointing at the private reload.
Python 3.9/3.10 mock follows that attribute, so
test_whisper_list_and_delete patched a different copy than it
imported and the expanduser stub hid the real cache.
Point the package attribute back at the restored module, and
patch the imported module object in the deletion test.
* feat(settings): delete unused downloaded speech models
Add a Remove Model dropdown on the Speech Model page so whisper.cpp,
Whisper, and VOSK downloads can be deleted from Settings. The currently
selected model is marked in use and cannot be removed until you switch
away from it.
Fixes#650
* fix(settings): move unused model deletion below the picker
Unused downloads is its own group under the model info card. Only leftover
files appear, each with a Delete button. The group hides when empty.
* fix(settings): collapse unused downloads into an expander
Keep leftover models behind one row so a long list does not stretch the
Speech Model page. Expand to delete files one at a time; the list scrolls
once it grows past a few entries.
* fix(settings): keep leftover model list from clipping in the expander
Wrap the unused-downloads list so the expander can show a few rows and
scroll the rest, instead of painting only the first leftover.
