Updates increment and decrement services in Spook to handle floating-point arithmetic inaccuracies.

• Replaces the strict equality check for step multiples with a tolerance-based check using math.isclose in custom_components/spook/ectoplasms/number/services/decrement.py and increment.py. This change addresses the issue of floating-point arithmetic inaccuracies when checking if an amount is a multiple of the step value.
• Applies the same tolerance-based check for step multiples in custom_components/spook/ectoplasms/input_number/services/decrement.py and increment.py, ensuring consistency across different types of number entities within Spook.

fixes #744

For more details, open the Copilot Workspace session.