Expose tab reordering as supported API so consumers can reorder tabs
without disposing and recreating items. Remap priority[] and firstIndex
to the items' new positions so chevron and visible-tab state stay correct.

Add moveItem(int from, int to) as an ergonomic primitive for the common
single-tab drag gesture, implemented on top of setItemOrder.

Bump the bundle minor version to 3.135.0 as required for the new API.