flush out Whisper functionality

[jackschedel]

• spinwait icon change on processing
• auto-stop and wait for process end on "save and submit"
• separate record+submit button
• option to auto-stop after 5s of silence (slider?)
• add usage to API cost

[jackschedel]

spinwait icon change on processing complete - implemented as Unicode marker character (that changes on record vs submit)

[jackschedel]

likely this plus #48 as a dedicated version release

[jackschedel]

auto-stop and wait for process end on "save and submit" no longer planned as whisper record now disables generate button