## Context

RTLSDR-Airband records CB transmissions as MP3 files into `/home/m/recordings/` on the Pi, organized by channel subdirectories with dated subdirectories inside. The recorder runs as a Docker container via `docker-compose.yml`.

## Goals / Non-Goals

**Goals:**
- Serve the recordings directory over HTTP with browsable directory listings
- Allow MP3 playback via the browser's native audio handling
- Deploy as a Docker container alongside the existing `sdr-recorder` service

**Non-Goals:**
- Custom web UI, styling, or JavaScript
- Authentication (local network only)
- Modifying, uploading, or deleting recordings
- Live streaming or transcription

## Decisions

### Use Nginx with HTML autoindex, no custom frontend

**Decision**: Use `nginx:alpine` with `autoindex on` to serve the recordings directory. No custom HTML, JS, or CSS.

**Rationale**: Nginx's built-in directory listing is fully functional for browsing channel/date directories. Modern browsers play MP3 files natively when clicked. This requires only an Nginx config file and a docker-compose service — zero application code.

**Alternatives considered**:
- **Custom SPA frontend**: Adds complexity (build tools, JS code) for marginal UX improvement over native directory listing.
- **Python http.server**: Simpler but less performant and no Alpine image parity.

## Risks / Trade-offs

- **[No search or filtering]** → Users browse by directory structure. Acceptable given the channel/date organization.
- **[Plain directory listing]** → No styled UI. Acceptable for a local utility tool.
- **[No auth]** → Anyone on the LAN can access. Acceptable per non-goals.