Rarely set fields move into one optional boxed NodeExtras, and large NodeKind payloads (images,
live shapes, blends, envelopes) are boxed. Every object, and every undo step that copies it,
shrinks: a 50k-path move keeps ~24.5 MB per step instead of ~40 MB. Files stay byte-identical
(Node keeps its flat JSON through a borrowed Serialize and a from-wire Deserialize, no flatten),
and loading is slightly faster. Undo and redo reuse their step's size estimate instead of
walking the document again (8.3 -> 5.6 ms for a 50k-path move).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VmMmc1J8XeNLxhRihWv9cc
# Conflicts:
# crates/engine/src/cmd/graph.rs
# crates/svg/src/export.rs
Clicking a Layers panel target circle runs `layer.target {id}`: a layer gets its art
selected and becomes the target (`Selection.target`) of the appearance, effect,
transparency and opacity-mask commands, which then edit the layer itself; the
Appearance panel lists it. Dragging a circle onto another runs
`appearance.transfer {source, target, copy?}` (Alt copies), dropping it on the trash
clears it. Filled dots also mark groups and layers with fills of their own, masked
objects get a dashed underline, and while an opacity mask is edited the panel lists
only an `<Opacity Mask>` entry and the tab says so.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>