Feature: expose Base Station (and Keypad) volume to HomeKit as a dimmer slider

[salmanesm]

Description

Summary

Expose the Ring Alarm Base Station (and optionally Keypads) volume to HomeKit so it can be adjusted directly from the Home app. The Ring API already supports setting volume; the Homebridge Ring plugin currently does not surface it.

Why

• Quickly lower/raise chimes without opening the Ring app.
• Enable scenes/automations that set system volume (e.g., “Night Mode” → quieter base station).
• Parity with other accessories that present a simple slider for intensity.

Proposed solution

• Service/UI: Use a Lightbulb service with Brightness (0–100) mapped to Ring volume 0.0–1.0 (value / 100) so the Home app shows a first-class slider.
  • (Optional) config to use (Television)Speaker with Volume characteristic instead.
• Devices: At minimum the Base Station; optionally Keypads if independently adjustable.
• Read/Write mapping:
  • GET: read current device volume → Math.round(volume * 100).
  • SET: HomeKit Brightness → setVolume(brightness / 100).
  • Consider a small update step (e.g., 5%) to reduce chatter.
• Config (opt-in):

  {
    "platform": "Ring",
    "exposeAlarmVolume": true,
    "volumeService": "lightbulb"
  }

• Implementation sketch: reuse the existing brightness-only accessory pattern; discover devices via location.getDevices() and wire to the Ring volume API.

Alternatives

Alternatives

- Use **(Television)Speaker** with **Volume** (semantic match but may be less prominent in Apple’s Home app).
- Expose **custom/Eve-only** characteristics (works in third-party apps; not ideal for stock Home).
- Do nothing (keep volume adjustments in the Ring app).


### Device data

**Expected behavior**
- A new accessory appears (e.g., “Ring Base Station Volume”) with a slider.
- Slider adjustments change device volume (0–100 → 0.0–1.0).
- Slider reflects current volume on refresh.