Add the progress line for the symbol editing follow-ups next to the Symbol
editing mode entry in docs/target-app-parity.md, with the tests that cover
them.
Symbol editing copies the editing layer's art into the symbol before Text Wrap, list numbering and threaded re-flow update that layer, so moving a wrap object in the edit left the symbol, its other instances and the saved file with the old wrap. The edit now syncs the symbol again after those passes, and when that changes the symbol, inline graphics of it are refreshed and the threads holding them re-flow.
The appearance changes of the instances on the layers now follow the edited objects through the same pass as the instances in other symbols, graph designs, pattern tiles and brushes. That pass also reaches instances used as opacity-mask art, which keep their changes on the same objects when an edit reorders them and drop the change to an object the edit deletes.
Entering symbol editing mode from an instance puts a copy of the symbol's art on the editing layer in the instance's place, and the instance stays in the document. The view drew the instance dimmed under the copy, so art with transparency showed darker, and its edges showed a dimmed fringe.
The renderer now leaves that instance out of the screen view while the editing layer is isolated, with its masks and effects, and in Outline view inside a clip group. Exports and thumbnails draw it as before.
Editing a dynamic symbol moved each placed instance's appearance changes with the objects they
name, but an instance stored in the art of another symbol kept its changes at the old paths, so
placing that symbol showed a change on the wrong object. Those instances, opacity masks included,
now follow the edit too and keep only the changes to objects the art still has.
symbol.edit checks the new placement before it ends the symbol being edited, so a call with an out-of-range x or y fails and leaves the current edit open. While a symbol is edited, object.isolate refuses art outside the editing layer, and object.exitIsolation goes back to the editing layer only from a group inside it; from any other isolation it leaves symbol editing mode.
Headless tests cover a double-click on a symbol in Thumbnail View and List View, the panel
menu's Edit Symbol with and without a selected instance, the Control bar's Edit Symbol button,
and the Control bar's Exit Symbol Editing Mode and Exit Isolation Mode buttons inside the
symbol's art. The panel's module comment now says a double-click opens the symbol in symbol
editing mode, and docs/mcp.md lists symbol.edit's ids parameter.
Horizontal Scale and Vertical Scale accept any number above 0 and at most 4000000 %, and Baseline Shift accepts -4000000 to 4000000 pt, the limits the document model keeps a character style in. Character Rotation is stored from -180 to 180 degrees, as text.setFormat stores it. A scale outside its limit shows the new message "{label} must be a number above 0 and at most {max}", translated in every catalog that has Basic Character Formats.
BFlat