fix(gui-v2): :key on RightDrawer dynamic body to remount on switch

Adds :key="component" to <component :is="Body"> so opening drawer B
while A is open fully remounts (A's instance/state can't leak into B) —
a real defect for a primary shell overlay. Same-name reopen still
relies on the body reacting to prop changes (documented inline).
Companion test asserts the cross-component switch swaps the body
cleanly (A unmounts, B mounts). Addresses the Task 5 code-review
Important finding.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/app/src/components-v2/layout/__tests__/RightDrawer.spec.ts

@@ -226,4 +226,35 @@ describe('RightDrawer', () => {
     // Graceful-empty-state text must NOT appear when a component is rendered
     expect(wrapper.text()).not.toContain('Geen inhoud')
   })
+
+  // -------------------------------------------------------------------------
+  // 7. Switching the open drawer component swaps the body cleanly
+  //    (the :key="component" remount guard — opening B while A is open
+  //     unmounts A and mounts B; A's DOM/state must not linger).
+  // -------------------------------------------------------------------------
+
+  it('remounts the body when the open drawer switches to another component', async () => {
+    const BodyA = defineComponent({ template: '<div class="body-a">A</div>' })
+    const BodyB = defineComponent({ template: '<div class="body-b">B</div>' })
+    const nameA = `${PREFIX}BodyA`
+    const nameB = `${PREFIX}BodyB`
+
+    registerDrawerComponent(nameA, BodyA)
+    registerDrawerComponent(nameB, BodyB)
+
+    const wrapper = mountDrawer()
+    const shell = useShellUiStore()
+
+    shell.openDrawer(nameA, { title: 'A' })
+    await wrapper.vm.$nextTick()
+    expect(wrapper.find('.body-a').exists()).toBe(true)
+    expect(wrapper.find('.body-b').exists()).toBe(false)
+
+    // Switch to B while the drawer is still open — :key change forces a
+    // full remount so A is gone and B is mounted (no stale A instance).
+    shell.openDrawer(nameB, { title: 'B' })
+    await wrapper.vm.$nextTick()
+    expect(wrapper.find('.body-b').exists()).toBe(true)
+    expect(wrapper.find('.body-a').exists()).toBe(false)
+  })
 })