Fix listener callback contracts across domain APIs

[Faerkeren]

Problem

Domain listener docstrings and annotations do not match the actual callback contract.

src/haclient/entity/base.py:33 defines ValueChangeHandler as (old_value, new_value). _schedule_value() calls handlers with two arguments at src/haclient/entity/base.py:175-189. State transition listeners are also dispatched with (old_state, new_state) at src/haclient/entity/base.py:146-148.

Many public domain APIs document a different contract:

• src/haclient/domains/light.py:26-40, where on_turn_on() says the callback is zero-argument.
• src/haclient/domains/light.py:58-71, where on_brightness_change() says the callback receives the new brightness value, not (old, new).
• src/haclient/domains/sensor.py:23-38, where on_value_change() says the callback receives the new state string, not (old, new).
• Similar zero-argument or single-value wording appears across switch, binary_sensor, cover, lock, media_player, timer, vacuum, valve, climate, and humidifier listeners.

The public signatures also use Any -> Any, so type checking does not protect users from registering callbacks with the documented but wrong arity.

Suggested Fix

Choose one callback contract and make it consistent.

Recommended: keep the existing runtime behavior of (old, new) because tests already assert that shape, then:

• Update every public listener docstring to say callbacks receive (old, new).
• Replace func: Any) -> Any with typed callables such as ValueChangeHandler or a domain-specific alias.
• Add targeted tests that registering a zero-argument callback either fails early with a clear error or is no longer documented as valid.
• If zero-argument transition callbacks are preferred, add adapter helpers so transition listeners actually receive zero arguments and update existing tests accordingly.

Rationale

This is a user-facing API correctness bug. A user following the docs will register callbacks that raise TypeError when events fire. The library catches and logs those exceptions, so the callback silently does nothing from the caller’s perspective.