Add elapsed recording timer with auto-stop and configurable max duration

[xROBERTINOx]

Summary

• Added a live elapsed timer (M:SS) displayed next to the waveform in the recording overlay
• Timer changes color as it approaches the limit (white → yellow at 30s remaining → red at 10s remaining)
• Recording auto-stops and transcribes when the time limit is reached (default: 2 minutes)
• Added a "Recording Limit" card in Settings → General where users can keep the default (120s) or set a custom duration (15–600s)
• Includes an info note warning that longer recordings take more time to transcribe

Files Modified

• Sources/RecordingOverlay.swift — Added ElapsedTimerView, elapsedSeconds/maxRecordingSeconds on overlay state, widened overlay panel to fit timer
• Sources/AppState.swift — Added maxRecordingSeconds as a persisted setting, recording timer with auto-stop logic
• Sources/SettingsView.swift — Added "Recording Limit" settings card with default/custom options

Why

Groq's Whisper transcription has a 20-second timeout. Uncompressed PCM audio at ~10 MB/min means recordings over ~3 minutes risk timing out. The 2-minute default provides a safe margin while covering typical dictation use cases.

[zachlatta]

Can you send a video showing this working? Thank you! Also FYI that it no longer uses uncompressed audio. Audio is now compressed.

[marcbodea]

Can you send a video showing this working? Thank you! Also FYI that it no longer uses uncompressed audio. Audio is now compressed.

Since this was merged #38, the theoretical time limit for a transcription to fit in groq's 25MB limit is around 12 minutes. I've ran a couple of tests on audio files with that length and it seems the transcription finishes in around 3-4 seconds, so the 20 second timeout should be plenty.

I would say this covers most dictation use cases, what would maybe make sense is a countdown timer when getting close to the limit (instead of permanent), but merging #43 complicates things significantly, making it hard to set good defaults based on provider/plan/etc. so it would be up to the user to manually set the time limit.