Expose idle_fan_mode and idle_action as HA select entities for external control

[florianmulatz]

Description

The device-level parameters idle_fan_mode and idle_action are currently static configuration fields — editable only through the RoomMind UI (roommind/rooms/save). There is no way to change them from outside RoomMind via a HA automation, dashboard input or schedule.

Exposing them as HA select entities would allow full dynamic control without any workaround automation.

Use case

Bedroom with Daikin multi-split AC configured as idle_action: fan_only + idle_fan_mode: low. During the day a higher fan speed is preferred for faster ventilation; at night low is correct. Currently this requires a separate climate.set_fan_mode automation that runs after RoomMind sets the mode — a fragile workaround that fights RoomMind's own 30-second control cycle and defeats the goal of RoomMind being the sole authoritative HVAC controller.

With an exposed select.roommind_<area>_idle_fan_mode entity, a single automation (or a Scheduler entry) could change the fan speed cleanly at the right time, and RoomMind picks it up on the next cycle with no conflict.

What already exists in the code

idle_fan_mode and idle_action are already first-class fields in the device data model:

• Validated in websocket_api.py (lines 313–314)
• Consumed in mpc_controller.py by async_idle_device() via get_idle_action()
• Shown in diagnostics.py

The runtime logic is complete. Only external entity exposure is missing.

Proposed solution

Add a select platform (select.py) that registers per-AC-device entities:

Entity	Options	Behaviour
select.roommind_<area>_idle_fan_mode	Dynamic: reads fan_modes from the underlying climate entity	Changing the entity persists the value to the device config; coordinator picks it up on the next cycle
select.roommind_<area>_idle_action	off, fan_only, setback (AC)	Same persistence mechanism; low option only offered for TRV-type devices

This follows the same pattern already used by switch.roommind_*_climate_control.

Relation to existing requests

• Allow climate mode to be controlled via external entity (input_select / automation) #221 (external entity for climate_mode): same architectural pattern, different parameter — could be implemented together.
• Smarter fan strategy for climate devices, including heat distribution support #254 (smarter fan strategy): complementary but broader; this request is narrower and only requires surfacing an already-existing field.
• Sepperate "When-Idle" actions for Comfort and ECO #250 (separate idle actions for Comfort/ECO): orthogonal — this request is about external control, not schedule-aware differentiation.

Alternatives considered

• Using roommind/override/set — temperature-only, does not cover device behaviour parameters.
• Writing directly to .storage/roommind — unsupported and fragile.
• Separate climate.set_fan_mode automation — the current workaround; creates a control conflict with RoomMind's own fan mode calls.

[wanltz]

It would be a high value addition.

I would prefer being with offset mode during the day and ventilation stopped to auto, while during the night being on fan only with low speed.