Add min and max volume functionality per player

[OzGav]

FRONTEND CHANGES: music-assistant/frontend#1569
Satisifies: https://github.com/orgs/music-assistant/discussions/3288

Add configurable min/max volume limits per player

Summary

• Adds per-player minimum and maximum volume configuration options (advanced settings under player controls)
• Volume commands (volume_set, volume_up, volume_down) are clamped to the configured range
• External volume changes (physical buttons, other apps) are corrected back into the allowed range
• Group volume adjustments respect each child player's individual min/max limits
• Volume limits are exposed to the frontend via extra_attributes for UI consumption (e.g. slider bounds)
• Config validation rejects min > max to prevent invalid states

Edge cases and functionality covered

cmd_volume_set — All explicit volume set commands are clamped to [min_volume, max_volume] before reaching the device, including when called programmatically or via API.

cmd_volume_up / cmd_volume_down — Step-based volume changes respect the limits. volume_up caps at max_volume instead of 100; volume_down floors at min_volume instead of 0.

External volume changes — When a device reports a volume change outside the allowed range (e.g. user pressed a physical volume button, or used a manufacturer app), the controller detects it in signal_player_state_update and fires a corrective cmd_volume_set to clamp it back.

Group volume — When adjusting group volume, each child player's individual min/max limits are respected. One child with max=50 won't be pushed to 80 just because the group volume goes up.

Config validation — on_player_config_change validates that min_volume <= max_volume and raises InvalidDataError if not

Falsy value handling — Uses explicit is not None checks rather than truthiness when reading config values, so min_volume=0 (a valid and common default) isn't incorrectly treated as missing.

Frontend exposure — extra_attributes property conditionally includes min_volume and max_volume only when they differ from defaults (0 and 100), so the frontend/HA integration can render appropriate slider bounds without noise in the default case.

Advanced settings — Both config entries are marked as advanced so they don't clutter the basic player settings for users who don't need them.

Default behavior unchanged — With defaults of min=0 and max=100, all existing behavior is preserved.

[oleost]

Thanks for trying to fix https://github.com/orgs/music-assistant/discussions/3288

Was wondering, would it be possible to implement also a option to scale the volume ?

Something like this:
https://github.com/oleost/server/tree/dev-max-volum-scale