[FEATURE] Add Accessible Resizable Panels Component

[VINAYMADIVAL]

Problem / Motivation

Currently, the DevUI component library lacks a resizable panel layout system that allows users to adjust content regions dynamically.
Such components are essential for dashboards, editors, and split-view layouts where users may need to resize sidebars or content panes.
The goal is to provide a fully accessible, keyboard-friendly, and pointer-draggable resizable layout consistent with DevUI’s styling and architecture.

Proposed Solution

Implement a new self-contained component set under src/components/Resizable.tsx, including:

• ResizablePanelGroup — main container that manages layout direction (horizontal or vertical).
• ResizablePanel — content panels that grow/shrink dynamically.
• ResizableHandle — interactive separator supporting mouse, touch, and keyboard resizing.

Key requirements:

• Smooth drag resizing with proper cursor feedback.
• Keyboard accessibility using arrow keys.
• ARIA roles (separator, aria-valuenow, aria-orientation) for screen reader support.
• No external dependencies; built entirely with React, Tailwind CSS, and the project’s cn() utility.
• Integrated demo preview (ResizablePanelGroup.Preview) for easy documentation.

Alternatives Considered

• Using existing libraries like react-resizable or react-split-pane, but they add unnecessary dependencies and inconsistent styling.
• Implementing minimal CSS-only resizers, which lack accessibility and keyboard controls.

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Acceptance Criteria

• Users can drag the handle to resize adjacent panels.
• Keyboard users can resize panels using arrow keys when the handle is focused.
• Layout works in both horizontal and vertical orientations.
• Component matches the visual style shown in the attached demo image (Sidebar | Handle | Content).
• No third-party dependencies are introduced.
• Proper documentation and preview entry are added to src/data/components.tsx.

[github-actions]

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• DevUI