Expose cleaning scenes as segments when native room support is unavailable

[ModernTTY]

Summary

This PR adds a fallback that exposes cleaning scenes as Home Assistant segments for devices that do not provide native room/segment information.

When native rooms are available, the existing behavior is unchanged. If no rooms are exposed but the device provides cleaning scenes, those scenes are exposed as segments instead. This enables Home Assistant’s native room mapping and segment cleaning UI on models such as the Eufy Omni C20.

Changes

• Fall back to scenes when no native room/segment data is available.
• Expose scene-based segments for Home Assistant room mapping.
• Route app_segment_clean and async_clean_segments to scene_clean when using scene-based segments.
• When multiple scene-based segments are selected, clean the first scene and log a warning (matching current device capabilities).
• Add regression tests covering the new fallback behavior.

Compatibility

• Devices with native room support continue to use native rooms.
• The scene fallback is only used when no native rooms are available.

Related Issues

#130

Attribution

The implementation in this PR is based on work by @acdu1. I cherry-picked the two scene-support commits from their fork so this feature can be reviewed independently of the other unrelated changes in that branch. All implementation credit goes to them.

[m11tch]

Thank you for your contribution, it seems like a useful addition, but I do have some minor remarks.

[m11tch]

Thanks, the production code now routes scene cleaning through self.coordinator.build_device_command(...), which addresses my previous protocol-routing concern.

There are two remaining items:

1. The updated tests still patch/assert custom_components.robovac_mqtt.vacuum.build_command, but the implementation now correctly calls self.coordinator.build_device_command(...). This currently makes pytest tests/test_vacuum.py -q fail with 4 failures. The tests should be updated to assert mock_coordinator.build_device_command instead.

2. The multiple-selection behavior is still concerning: clean_segments(["1", "2"]) only cleans the first scene-backed segment and logs a warning. Since HA segment cleaning semantically accepts multiple selected segments, I’d prefer either raising HomeAssistantError for multiple scene-backed IDs or not exposing scene-backed segments as multi-select-capable.

[ModernTTY]

@m11tch Done in latest commit.

[acdu1]

@ModernTTY Thanks for helping me!

[m11tch]

Thank you for your contribution, Please fix the linting issues, after that I think we're good to merge :)

[ModernTTY]

@m11tch Done in latest commit.

[m11tch]

@m11tch Done in latest commit.

checks are still failing

[ModernTTY]

@m11tch Lint should pass now