* ✨ Show color tokens toggle on canvas background picker
* 🐛 Apply token click on canvas background with no shape selected
* ✨ Apply and persist color tokens on canvas background
* 🌐 Translate canvas background section label
Repair text shapes with empty/broken content at all three levels
(root, paragraph-set, paragraph) in migration 0025 to prevent
workspace update failures. Handle all corner cases: nil/empty/non-
vector children, non-map items, wrong types. Remove geometry-only
validation skip in changes.cljc so all shapes are validated.
AI-assisted-by: qwen3.7-plus
