feat(resizable): add animated collapse/expand methods to ResizablePanel

[bob-obringer]

Summary

• Added animatedCollapse() and animatedExpand() methods to the ResizablePanel imperative handle
• Enables smooth CSS transitions when programmatically collapsing/expanding panels
• Drag resizing remains instant (transition is only applied temporarily during animated methods)

Changes

• resizable.tsx: Extended ResizablePanelImperativeHandle type with new animated methods that use direct DOM manipulation on the data-panel element
• resizable.stories.tsx: Added AnimatedCollapse story demonstrating animated vs instant toggle
• package.json: Version bump to 1.2.0
• CHANGELOG.md: Added 1.2.0 entry

Usage

const panelRef = useRef<ResizablePanelImperativeHandle>(null);

// Smooth animated collapse/expand
panelRef.current?.animatedCollapse();
panelRef.current?.animatedExpand();

// Original instant collapse/expand (still available)
panelRef.current?.collapse();
panelRef.current?.expand();

Test plan

• Verified animation works in Storybook
• Confirmed drag resizing has no animation lag
• Build passes

🤖 Generated with Claude Code

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Project	Deployment	Review	Updated (UTC)
ui	Ready	Preview, Comment	Jan 20, 2026 11:47pm