* fix(ui): release modal grab after TinyDiarize download before transcript opens
The transcribe path's ModelDownloadDialog is modal. On success it stayed
open behind the diarized transcript dialog, holding its grab so every
button on the transcript was unclickable until the hidden dialog was
found and closed. Destroy it on success there and let the transcript be
the completion affordance; the failure path still keeps the dialog up to
show the error.
* style(tests): black-format new dialog-grab tests
* fix(ui): stop download dialog pulse timer on destroy; type test helper
* style(ui): type destroy-handler varargs
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Co-authored-by: Jatin K Malik <jatinkrmalik@gmail.com>
