volume has no effect

Model Name: iPhone: 15 Pro Max
Software Version: 26.5.2
App version: 2026.7.1 (2026.2346)

**Home Assistant Core Version**
2026.7.4

**Describe the bug**
From the [docs](https://companion.home-assistant.io/docs/notifications/notifications-basic) (as I have interpreted them), the following should send a loud tone provided the phone is not on silent and the sound in question has been imported:

However, that volume command has no bearing on the actual volume of the notification; I can set it to `0.0`, `0.5`, `1.0` or even remove it and the volume remains the same.

Also, if I add `critical: 1`, I get full volume whether `volume:` is there or not so, `volume:` is irrelevant (or not working).

**To Reproduce**
The following **does not** produce full volume:
```yaml
action: notify.mobile_app_monkeybutler
data:
title: "test"
message: "test"
data:
push:
interruption-level: time-sensitive
sound:
name: "Bloom.caf"
volume: 1.0
```
**Expected behavior**
I expect full volume.

**Screenshots**

**Additional context**

Start with the linked notifications documentation and reproduce the YAML payload on an iPhone 15 Pro Max running the reported app and core versions. Trace how the iOS app handles the push sound name, volume, interruption level, and critical flag; done means confirming volume changes notification loudness or documenting the platform limitation and correcting the behavior or docs.

Written by the indexing model from the issue text.