- two tabs only: 'Plan editor' / 'Device editor'; View is the implicit
default state, no tab
- Device editor gets its own bottom toolbar (add/show-all/reset/rules
moved from the header), mirroring the Plan toolbar
- X button on both toolbars and inside the active tab returns to View;
re-click on active tab is a no-op; Plan<->Devices switches directly
- smoke_editor_tabs.mjs; TESTING/CHANGELOG/UX-MODES same-commit
