Feature (json-path-finder): improve tree view and add input utilities

[drakehanguyen]

• Fix truncated JS output: collapsed objects/arrays now display as {n}/{[n]} instead of "Object (n items)"
• Add tree connector lines (├/└) to clarify node hierarchy
• Move copy-path button to left side with path shown as hover tooltip
• Add key sorting (A-Z / Z-A) to tree view footer
• Add file upload, load-from-URL, and download results features
• Export sortObjectKeys from json-formatter lib for reuse

Description

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📝 Documentation update
• ♻️ Code refactoring (no functional changes)
• ⚡ Performance improvement
• ✅ Test addition or update
• 🎨 Style/formatting changes (no functional changes)
• 🔧 Configuration changes
• 🔒 Security fix

Related Issue

Closes #
Related to #

Changes Made

Testing

• ✅ All existing tests pass
• ✅ New tests added for new functionality
• ✅ Manual testing completed
• ✅ Tested on multiple browsers (if applicable)
• ✅ Tested on mobile devices (if applicable)

Test Steps

Screenshots (if applicable)

Before	After

Checklist

Code Quality

• Code follows the project's style guidelines
• Self-review of code completed
• Comments added for complex code/logic
• No console.log statements left in code
• No commented-out code
• Code is properly formatted (Prettier)

TypeScript

• TypeScript types are properly defined
• No any types used (unless necessary)
• Type checking passes (pnpm type-check)

Linting & Formatting

• ESLint passes (pnpm lint)
• Code is properly formatted (pnpm format:check)

Testing

• Unit tests added/updated
• All tests pass (pnpm test)
• Test coverage maintained or improved

Documentation

• README.md updated (if applicable)
• CHANGELOG.md updated (if applicable)
• Code comments added/updated
• JSDoc comments added for public APIs (if applicable)

Build & Deployment

• Build succeeds (pnpm build)
• No build warnings or errors
• Production build tested locally

Accessibility

• Accessibility considerations addressed
• Keyboard navigation works (if applicable)
• Screen reader tested (if applicable)

Browser Compatibility

• Tested on Chrome
• Tested on Firefox
• Tested on Safari
• Tested on Edge (if applicable)
• Mobile responsive (if applicable)

Performance

• No performance regressions
• Bundle size impact considered
• Lazy loading used where appropriate

Additional Notes

Breaking Changes

Migration Guide