Fix #681: Rearrange All Artboards layouts, order and one-click access

- artboard.rearrange takes layout (gridByRow, gridByColumn, row, column;
  byColumn stays as an alias of gridByColumn) and order (leftToRight,
  rightToLeft); Columns is the row count of a grid by column and is
  ignored by row and column. It returns {artboards, rows, columns}.
- A Rearrange All Artboards dialog: Layout and Layout Order toggles drawn
  in code (widgets::layout_button, previewing the order), Columns/Rows,
  Spacing, Move Artwork with Artboard and the artboard count.
- One click: Rearrange All in the Properties panel (Document section with
  several artboards, Edit Artboards' Quick Actions); the Artboards panel's
  Rearrange button and menu item now open the dialog too.
- Tests for every layout x order (artboards, art riding along, one undo
  step), the dialog, the Properties button; the command sweep covers the
  new params. Translations for ja, es, it, ru, fr, zh-hans, zh-hant and
  pt-br; ROADMAP updated.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ui-egui/src/dialogs/command.rs

@@ -24,7 +24,6 @@ fn lengths(command: &str) -> &'static [&'static str] {
     match command {
         "graph.create" => &["width", "height"],
         "shape.flare" => &["diameter", "pathLength"],
-        "artboard.rearrange" => &["spacing"],
         "perspective.grid.set" => &["cell", "distance"],
         "object.repeat.options" => &["radius", "hSpacing", "vSpacing"],
         "text.areaOptions" => &["width", "height", "gutter", "inset", "firstBaselineMin"],