push和pod会导致路由栈中的所有widget重新rebuild

A -> B - > C -> D，A、B、C、D是Flutter页面，没有使用新的native容器承载，不管是push还是pop都会使路由栈中所有的widget都会重复走多次build，页面越多，单个页面被build次数越多

Reproduce the issue with Flutter pages arranged as A → B → C → D, using both push and pop without the new native container. Observe how often each route's widgets rebuild as the stack grows. Done means the intended rebuild behavior is confirmed and the excessive rebuilds are addressed with coverage for both navigation directions.

Written by the indexing model from the issue text.