Feature Request: Support for soft transitions (fade time) for model H1630

[saschachina]

Is your feature request related to a problem? Please describe.

While the lights (like my H1630 Lantern Floor Lamp) naturally fade in softly when turned on/off (due to Govee's built-in default behavior), it is currently not possible to control or change the duration of these transitions. When changing colors or brightness levels, the lights jump directly to the new values without a controllable smooth fade.

Describe the solution you'd like

I would like govee2mqtt to support the standard Home Assistant transition attribute. This would allow users to specify a custom duration (in seconds) for color and brightness changes, enabling effects like slow evening dimming or customized scene fades.

Describe alternatives you've considered

I tried using a Home Assistant script, it works but it´s not the elegant solution:

alias: Govee H1630 transition test
sequence:
  - repeat:
      while:
        - condition: template
          value_template: "{{ state_attr('light.stehlampe', 'brightness') | int(0) < 255 }}"
      sequence:
        - target:
            entity_id:
              - light.stehlampe
          data:
            brightness_step: 13
          action: light.turn_on
        - delay:
            hours: 0
            minutes: 0
            seconds: 2
            milliseconds: 0
mode: single

Additional context

My device is a Govee H1630 operating entirely via the Local LAN API. Since local control doesn't suffer from cloud rate limits or internet latency, having the integration handle or smoothly inject these transitions would make the lighting experience much more premium.

Thank you for your hard work on this project!