### Requirement: Serve recordings directory over HTTP
The system SHALL serve the contents of the recordings directory via an Nginx web server with directory listing enabled.

#### Scenario: Browse channel directories
- **WHEN** a user navigates to the root URL of the web server
- **THEN** the server displays a directory listing showing the channel subdirectories

#### Scenario: Browse date directories within a channel
- **WHEN** a user clicks a channel directory
- **THEN** the server displays a directory listing of date subdirectories for that channel

#### Scenario: Browse recording files within a date
- **WHEN** a user clicks a date directory
- **THEN** the server displays a listing of MP3 recording files

### Requirement: Browser-native MP3 playback
The system SHALL serve MP3 files with correct MIME type so browsers can play them natively.

#### Scenario: Play a recording
- **WHEN** a user clicks an MP3 file link in the directory listing
- **THEN** the browser opens and plays the MP3 file using its native audio player

### Requirement: Docker deployment
The web server SHALL run as a Docker container defined in `docker-compose.yml`, mounting the recordings directory read-only.

#### Scenario: Start alongside recorder
- **WHEN** a user runs `docker compose up` on the Pi
- **THEN** the Nginx service starts alongside the `sdr-recorder` service and is accessible via HTTP

#### Scenario: Read-only access to recordings
- **WHEN** the Nginx container accesses the recordings volume
- **THEN** the volume is mounted read-only, preventing modification of recording files