Three new QUndoCommand subclasses (AddDiagramCommand, RemoveDiagramCommand,
MoveDiagramCommand) pushed onto the project's existing (already
project-scoped) undo stack, so folio structure edits are undoable
alongside every item-level edit already on that stack.
- QETProject::addDiagram()/detachDiagram() are the shared attach/detach
primitives: they mutate the diagram list, connect/disconnect the two
per-diagram signals set up at add time, and emit diagramAdded/
diagramRemoved. AddDiagramCommand and RemoveDiagramCommand call these
(via friend access) for both redo and undo, so a removed diagram is
parked rather than destroyed -- it's only actually deleted if the
command itself falls out of undo history while still detached.
- ProjectView reacts to diagramRemoved the same way it already reacted to
diagramAdded (tearing down/rebuilding the tab), so both directions of
both commands go through the same reactive path every other diagram
listener (project database, cross-references, generic panel) already
relies on.
- MoveDiagramCommand wraps a new ProjectView::setDiagramPosition(), which
performs the tab move and the project's diagramOrderChanged() list
reorder synchronously in one step, instead of relying on the queued
tabMoved connection (needed for interactive drag-and-drop) to catch up
later -- avoiding a second, redundant reorder from that queued call.
- Multi-folio delete and multi-folio move (QETDiagramEditor::removeDiagrams()
and the moveDiagram*(QList<Diagram*>) batch slots) wrap their per-diagram
loop in QUndoStack::beginMacro()/endMacro(), so a multi-select action is
one undo step, matching current UX.
- Softened the delete confirmation's "this change is irreversible" wording
now that it no longer is.
Verified headlessly (Xvfb + xdotool + scrot): add/undo/redo, delete/undo/
redo (single and multi-select, single undo step for the batch), and
move/undo/redo all behave correctly against a 7-folio project.