Add resume/manual transcription feature for pending audio files

[hyper-charlie]

Feature Request: Resume Transcription & Summary Processing

Problem

When users close the app during or before transcription/summary generation completes (especially after offline meetings), the processing halts. Users often need to move on and cannot wait for processing to finish. Currently, audio files are captured but the processing cannot be resumed later.

Desired Solution

Implement a resume/manual transcription feature that allows users to:

1. Manual Processing: Request transcription and summary generation on-demand for pending audio files (rather than automatic background processing)
2. Pending Queue Dashboard: Display a dedicated section showing all recordings awaiting transcription/summary with their status
3. Scope: Apply to both online meetings (via calendar integration) and offline meetings
4. Background Processing: Support background processing while the app is running (without requiring active user focus on that session), while preserving source audio.mp3 files

Use Case

1. User completes an offline meeting and captures audio
2. User closes the app without waiting for transcription/summary to complete
3. Later, user opens the app and sees a "Pending Transcriptions" dashboard
4. User selects which recordings to process and manually triggers transcription/summary
5. Processing occurs in the background while user continues using the app
6. Original audio files are retained (not deleted after processing)

Benefits

• Users can capture audio without blocking their workflow
• Flexible scheduling of resource-intensive processing
• Audio files remain available for re-processing or manual review
• Improved UX for users with time-constrained workflows