program_path takes the custom path as its second argument, and config.py
passes it, but the settings window never did. Happened on this machine:
Compiled my own whisper.cpp and llama.cpp with CUDA and pointed the
settings at them. The box with no downloaded copy said "Not installed."
The box with one said "Downloaded, version b4938." naming a processor
build while the CUDA one did the transcribing.
LocalModelBox is now handed a callable, so the setting is read when
the label is drawn rather than frozen when the window is built.
The label reflects that too. A path set by hand now says so, instead of
claiming Dikte downloaded something it didn't.
