Manually deleting phases left their parent changeset as "applied",
causing the Plan tab to show a stale "Created N phases" banner with
no phases visible.
- deletePhase now checks if all phases from a changeset are gone and
marks it reverted
- PlanSection filters out dismissed agents so dismissed banners stay
hidden
- revertChangeSet marks reverted before entity deletion to prevent
ghost state on partial failure
- deletePhase invalidation now includes listChangeSets
39bb03e30b