## ADDED Requirements

### Requirement: Model Download Progress Display
The sidecar SHALL report Whisper model download progress to enable UI feedback.

#### Scenario: Emit download start
- **WHEN** Whisper model download begins
- **THEN** sidecar SHALL emit JSON to stdout: `{"status": "downloading_model", "model": "<size>", "progress": 0, "total_mb": <size>}`

#### Scenario: Emit download progress
- **WHEN** download progress updates
- **THEN** sidecar SHALL emit JSON: `{"status": "downloading_model", "progress": <percent>, "downloaded_mb": <current>, "total_mb": <total>}`
- **AND** progress updates SHALL occur at least every 5% or every 5 seconds

#### Scenario: Emit download complete
- **WHEN** model download completes
- **THEN** sidecar SHALL emit JSON: `{"status": "model_downloaded", "model": "<size>"}`
- **AND** proceed to model loading

#### Scenario: Skip download for cached model
- **WHEN** model already exists in huggingface cache
- **THEN** sidecar SHALL NOT emit download progress messages
- **AND** proceed directly to loading

### Requirement: Frontend Model Download Progress Display
The Electron frontend SHALL display model download progress to users.

#### Scenario: Show download progress in transcript panel
- **WHEN** sidecar emits download progress
- **THEN** whisper status element SHALL display download percentage and size
- **AND** format: "Downloading: XX% (YYY MB / ZZZ MB)"

#### Scenario: Show download complete
- **WHEN** sidecar emits model_downloaded status
- **THEN** whisper status element SHALL briefly show "Model downloaded"
- **AND** transition to loading state

#### Scenario: Forward progress events via IPC
- **WHEN** main process receives download progress from sidecar
- **THEN** it SHALL forward to renderer via `model-download-progress` IPC channel