Enhance tests for WeightStore with new operations and metrics validation (#44)

* Enhance tests for WeightStore with new operations and metrics validation

- Added tests for weight tracking, including rejection of updates exceeding capacity.
- Introduced metrics validation for insertions, removals, and evictions.
- Implemented property-based tests to ensure state invariants under random operations.
- Improved coverage for edge cases, such as zero weight capacity and weight overflow scenarios.

* Refactor test assertions in WeightStore for improved readability

- Reformatted assertions in the `weight_store_clear_resets_contents_but_preserves_counters` and `weight_store_clear_resets_contents_but_preserves_counters` tests for better clarity.
- Ensured consistent formatting across test cases to enhance maintainability and readability.

Author: TKorr