Fix parent composite status after ghost child cleanup

[Copilot]

During composite instance updates, parent composites were incorrectly included in the destroy phase alongside their ghost children, causing their operation status to be marked as "destroyed" instead of "updated".

Changes

• operation-plan.ts: Modified findGhostCleanup() to only add ghost children to the destroy phase, not their parent composites
• operation-plan.update.test.ts: Updated test expectations for ghost cleanup scenarios (tests 5, 5a, 16)

Impact

Ghost children (virtual instances without evaluation state) are still cleaned up correctly, but parent composites now maintain proper deployment status through the update operation.

Before:

// Parent composite was added to destroy phase
ghosts.push({
  id: instanceId,  // parent composite
  parentId: instance.parentId,
  message: "included in operation",
})

After:

// Only ghost children are added to destroy phase
if (isVirtualGhostInstance(state)) {
  ghosts.push({
    id: child.id,  // ghost child only
    parentId: child.parentId,
    message: "ghost cleanup",
  })
}

Original prompt

when updating composite instance, after ghost clean up parent instance became undeployed with operation state destroyed, while deployed/updated must be kept instead

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