[TWRNC] Added test suite

[brianacnguyen]

Description

This PR adds a comprehensive test suite for the package @metamask/design-system-twrnc-preset

Related issues

Fixes: #732

Manual testing steps

1. Go to packages/design-system-twrnc-preset
2. Run yarn test

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

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[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	@​babel/​runtime@​7.26.0 ⏵ 7.27.6	+1	+5

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[cursor]

✅ BugBot reviewed your changes and found no bugs!

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[Copilot]

Pull Request Overview

This PR adds a comprehensive test suite for the @metamask/design-system-twrnc-preset package, addressing issue #732. The test suite includes complete coverage for all major components and functionality of the design system preset.

• Adds unit tests for all modules including typography, colors, themes, hooks, and configuration generation
• Adds test infrastructure with Jest configuration and proper coverage settings
• Includes a minor bug fix in the colors module's flattenColors function

Reviewed Changes

Copilot reviewed 11 out of 12 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/typography.types.test.ts	Tests for typography type definitions and interfaces
src/typography.test.ts	Tests for typography configuration and design tokens
src/tailwind.config.test.ts	Tests for Tailwind configuration generation logic
src/index.test.ts	Tests for package exports and public API
src/hooks.test.tsx	Tests for React hooks (useTheme, useTailwind)
src/colors.test.ts	Tests for color system and theme color handling
src/ThemeProvider.test.tsx	Tests for React context provider component
src/Theme.types.test.ts	Tests for theme enum and type definitions
src/colors.ts	Bug fix for flattenColors function logic
package.json	Added react-native dev dependency for testing
jest.config.js	Updated Jest configuration with coverage settings

[Copilot]

The logic change from else if to separate if statements will cause string values to be processed twice - once as strings and once as potential objects. This could lead to incorrect flattening behavior where string values might be treated as objects if they have object-like properties.

Suggested change

	}
	if (typeof value === 'object' && value !== null) {
	} else if (typeof value === 'object' && value !== null) {

[georgewrmarshall]

@cursoragent review