feat: add support for snap points

[rijkvanzanten]

Closes #18

[Copilot]

Pull Request Overview

This PR adds snap point functionality to the SplitPanel component, allowing the divider to automatically snap to predefined positions during drag operations and double-click interactions.

• Implements a utility function to find the closest number from an array
• Adds snap point logic to the SplitPanel component with configurable threshold
• Provides double-click functionality to jump to the nearest snap point

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
closest-number.ts	New utility function to find the closest value from an array with proper tie-breaking
closest-number.test.ts	Comprehensive test suite for the closest number utility
SplitPanel.vue	Adds snap points props, snap logic during drag, and double-click snap behavior
App.vue	Updates playground to demonstrate snap points at 25% and 50%
usage.md	Documents the new snapPoints and snapThreshold properties
ExampleSnap.vue	New documentation example component demonstrating snap functionality

Comments suppressed due to low confidence (1)

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}