feat: enhance UI with custom sort dropdown, resizable layouts, StackView DnD, and optimize slider/resize performance with layout fixes.

docs/development/devlog/2025-12-18-034500_slider_optimization.md

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+# Work Plan - Optimize Card Slider Performance
+
+## Request
+The user reported that resize handlers (likely sliders) were still laggy.
+
+## Changes
+- **DraftView.tsx**:
+    - Introduced `localCardScale` for immediate slider feedback.
+    - Used CSS Variable `--card-scale` on container to update card sizes entirely via CSS during drag.
+    - Deferred `cardScale` state update (which triggers React re-renders) to `onMouseUp`.
+
+- **DeckBuilderView.tsx**:
+    - Introduced `localCardWidth` for immediate slider feedback.
+    - Used CSS Variable `--card-width` on container.
+    - Updated `gridTemplateColumns` to use `var(--card-width)`.
+    - Deferred `cardWidth` state update to `onMouseUp`.
+    - Cleaned up duplicate state declarations causing lint errors.
+
+- **CubeManager.tsx**:
+    - Introduced `localCardWidth` and CSS Variable `--card-width`.
+    - Updated Grid layout to use CSS Variable.
+    - Deferred state update to `onMouseUp`.
+
+## Verification
+- **Performance**: Slider dragging should now be 60fps smooth as it touches 0 React components during the drag, only updating a single CSS variable on the root container.
+- **Persistence**: Releasing the slider saves the value to state and localStorage.
+- **Logic**: complex logic like `useArtCrop` (which depends on specific widths) updates safely on release, preventing flicker or heavy recalculations during drag.