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

docs/development/devlog/2025-12-18-033000_resize_optimization.md

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+# Work Plan - Optimize Resize Performance
+
+## Request
+The user reported that the resize functionality was laggy, slow, and inconsistent.
+
+## Changes
+- **Refactoring Strategy**:
+    - Removed React state updates from the `mousemove` event loop.
+    - Used `useRef` to track `sidebarWidth` and `poolHeight` values.
+    - Used `requestAnimationFrame` to throttle DOM updates directly during resizing.
+    - Only triggered React state updates (re-renders) on `mouseup`.
+
+- **DraftView.tsx**:
+    - Implemented `resizingState` ref.
+    - Modified `handleMouseDown` to initiate direct DOM resizing.
+    - Modified `onMouseMove` to update element styles directly.
+    - Modified `onMouseUp` to sync final size to React state.
+    - Applied refs to Sidebar and Pool resizing areas.
+
+- **DeckBuilderView.tsx**:
+    - Implemented identical ref-based + requestAnimationFrame resizing logic.
+    - Fixed several HTML nesting errors introduced during the complex refactoring process.
+
+## Verification
+- **Performance**: Resizing should now be smooth (60fps) as it avoids React reconciliation during the drag.
+- **Consistency**: The handle should no longer "slip" because the visual update is faster.
+- **Persistence**: The final size is still saved to `state` (and thus `localStorage`) after release.