fix & feat: maintain equal spacing between page indicators and add option to disable item position adjustment for multiple items

[zhongzhenwu]

This pull request includes the following changes:

1. fix: Ensure equal spacing between page indicators even when the selected and unselected indicators have different path values.
2. feat: Add an option to disable automatic position adjustment when displaying multiple items per page.
   For example, when displaying two items per page, the default behavior centers one item and shows half an item on each side. This feature allows developers to retain the original item layout without forced centering.

Tested locally and works as expected.
Looking forward to your review. 🙏

[zhongzhenwu]

@WenchaoD Hi, would you mind reviewing this PR when you have time? Thanks a lot!