fix(runtime-vapor): unmount leaving KeepAlive cache entries

Summary:
- remove cached branches from their actual parent during teardown
- preserve logical unmount when a cached branch is already detached
- cover KeepAlive unmount during a pending deactivation leave

Author: edison1105

packages/runtime-vapor/__tests__/components/KeepAlive.spec.ts

@@ -1376,6 +1376,41 @@ describe('VaporKeepAlive', () => {
       app.unmount()
     })
 
+    test('unmounts a cached branch with a pending deactivation leave', async () => {
+      const CompA = compile(`<template><div>A</div></template>`, ref())
+      const CompB = compile(`<template><div>B</div></template>`, ref())
+      const leaves: Array<() => void> = []
+      const data = shallowRef({
+        current: CompA,
+        onLeave: (_el: Element, done: () => void) => leaves.push(done),
+      })
+      const App = compile(
+        `<template>
+          <Transition :css="false" @leave="data.onLeave">
+            <KeepAlive :max="2">
+              <component :is="data.current" />
+            </KeepAlive>
+          </Transition>
+        </template>`,
+        data,
+      )
+      const { host, app } = define(App as any).render()
+      const a = host.firstElementChild
+
+      data.value = { ...data.value, current: CompB }
+      await nextTick()
+
+      expect(leaves).toHaveLength(1)
+      expect(a!.parentNode).toBe(host)
+      expect(() => app.unmount()).not.toThrow()
+      expect(host.innerHTML).toBe('')
+      expect(leaves).toHaveLength(1)
+
+      leaves[0]()
+      await nextTick()
+      expect(host.innerHTML).toBe('')
+    })
+
     test('unmounts an incoming branch superseded during mount', async () => {
       const deactivatedB = vi.fn()
       const unmountedB = vi.fn()

packages/runtime-vapor/src/components/KeepAlive.ts

@@ -170,7 +170,6 @@ const VaporKeepAliveImpl = defineVaporComponent({
       block: VaporComponentInstance | VaporFragment,
       isCurrent: boolean,
     ) => {
-
       if (cache.has(key)) {
         if (isCurrent) {
           // Only active branches should refresh their recency. Background
@@ -357,7 +356,9 @@ const VaporKeepAliveImpl = defineVaporComponent({
         }
 
         unsetShapeFlag(cached)
-        remove(cached, storageContainer)
+        // A cached branch may still be leaving in its live parent.
+        const parentNode = findBlockBoundary(cached).parentNode
+        remove(cached, (parentNode as ParentNode | null) || undefined)
       })
 
       // Same-tick branch switches can tear down KeepAlive after the next branch