* 🐛 Update canvas background when its color token changes
Token propagation only walked the shapes of each page, so a canvas
background linked to a color token kept its old value after switching
the active set or editing the token. Propagation now also updates the
background of every page whose `:background-token` resolves to a new
color, inside the same undo transaction.
AI-assisted-by: claude-opus-5-5
* 🐛 Select the dragged token set by id instead of by path
Starting a drag on an unselected token set stored its path as
`:selected-token-set-id`. The sidebar then crashed on the
`(uuid? force-set-id)` assert of `get-tokens-in-active-sets-force`.
This could happen when toggling a set checkbox with a slight mouse
move.
AI-assisted-by: claude-opus-5-5
* 🎉 Add playwright test