Modernize entity lifecycle and handle unavailable humidity sensorsUpdate binary_sensor.py

[Corsw]

Summary

This pull request modernizes the binary sensor entity while preserving the
existing periodic humidity-rise detection behaviour.

Changes

• Use BinarySensorEntity
• Register the periodic callback in async_added_to_hass
• Automatically remove the callback when the entity is removed
• Disable Home Assistant polling because the entity manages its own interval
• Treat missing, unknown and unavailable source sensors as temporary states
• Mark the entity unavailable while the source sensor is unavailable
• Preserve warnings for invalid sensor values or missing attributes
• Validate that sample_interval is greater than zero
• Prevent an empty sample buffer
• Safely handle calculations before samples are available
• Check max_on_time even while the source sensor is unavailable
• Prevent immediate reactivation after max_on_time
• Use extra_state_attributes
• Add readable debugging values for the target and timers
• Add state-dependent water icons

Behaviour preserved

The integration still samples the source sensor periodically and compares the
current humidity with the lowest sample in the configured sample window. It
has not been converted to state-change-based sampling.

Testing

Tested on my Home Assistant installation with:

• startup while the source humidity sensor is unknown
• normal off state
• humidity samples updating
• entity availability recovery
• state-dependent icons
• readable target and timer attributes

The startup warnings from issue #30 no longer occur for normal temporary
unknown or unavailable states.

[Corsw]

Hi Bas,

You mentioned previously that someone would be welcome to take over and
improve the integration.

I use this integration myself and have prepared a draft pull request that modernizes the entity lifecycle and fixes the startup handling while preserving the existing behaviour.

I would be willing to maintain the integration going forward.

Would you be open to reviewing the pull request and discussing either
maintainer access or transferring the repository?