Refactor code structure for improved readability and maintainability

[azebro]

This pull request improves support for H-firmware TAPs in the parser by relaxing validation of the status_type bits in RECEIVE_RESPONSE frames, updating documentation to clarify the bitmask meaning, and adding new tests to ensure compatibility with both G-firmware and H-firmware. It also refines the coordinator save scheduling logic to use a throttle pattern for more robust state persistence.

Parser and protocol improvements:

• Updated the _handle_receive_response method in parser.py to no longer validate bits 5-7 of status_type, allowing H-firmware frames (with bits 5-7 cleared) to be parsed correctly. Only bits 0-4 are now used to determine optional fields.
• Added comprehensive tests in test_parser.py to verify that RECEIVE_RESPONSE parsing works for both H-firmware (bits 5-7 cleared) and G-firmware (bits 5-7 set), including power report extraction and handling of empty responses.

Documentation updates:

• Revised implementation_plan.md to clarify that bits 5-7 of status_type are firmware-dependent flags with no effect on payload structure, and removed the requirement to validate these bits. [1] [2]

Coordinator state persistence:

• Changed the _schedule_save logic in coordinator.py to use a throttle pattern instead of debounce, ensuring that state saves are not repeatedly rescheduled under rapid updates and are always persisted within the expected delay window.