[mohammedFawzy0111]

Description

refactor the Node class to to seprate calsses for LeafNode and InternalNode instead of depending on a boolean.

Closes #339

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

Key Changes

• add LeafNode class.
• add InternalNode class.
• Remove Node class and replace it with a type alias to LeafNode and InternalNode.
• refactor PageSerializer.serialize() to work with the new classes.
• refactor PageSerializer.deserialize() to work with the new classes.
• updated tests for the new classes and remove unnecessary tests.

Validation

• all pre-commit hooks passed.
• formated using ruff format .
• ty check passed.

Checklist

• I reviewed the diff and kept it focused on the described change.
• Python changes pass uv run ruff check . and uv run ruff format --check ., or this PR does not change Python.
• Changed behavior is covered by appropriate tests, including a regression test for bug fixes; any limitations are explained under Validation.
• Validation lists the checks or manual flows I ran and their results.
• Relevant documentation is updated, or no documentation change is needed.

[mattsva]

lgtm

@mohammedFawzy0111 please tell @sowashieristjaschoninteressant in PR #338 what needs to be changed there to make it work.

[mattsva]

Merging this.