* 🐛 Clamp gradient stop offsets to valid [0, 1] range
Fixed a bug where gradient stop offsets outside the valid [0, 1] range were being sent to the server, causing schema validation errors ('invalid shape found').
Changes:
- Viewport gradient handler: clamp offset in points-on-pointer-down before creating new stops
- Colorpicker gradient preview: clamp offset in handle-preview-down before adding stops
- Data layer: clamp offset parameter in update-colorpicker-add-stop and all stop offsets in update-colorpicker-stops; added app.common.math require
All clamping follows the existing pattern used in handle-marker-pointer-move.
AI-assisted-by: deepseek-v4-flash
* 💄 Fix formatting in gradient handlers
Fix cljfmt formatting issues in gradient handler functions.
AI-assisted-by: qwen3.7-plus
fadb3124a0