fix: update and replace onboarding modal

[justlevine]

Description

Fixes loading of the onboarding site type modal, and replaces the js to typescript.

Based on #49 which should be merged first.

Technical Details

• Typescript
• Asset enqueing is colocated with the function
• uses settings API and nonce (built in perms) along with apiFetch to CRUD the site type
• loads on all OP screens + settings page
• full TS rewrite

Checklist

Screenshots

To-do

Fixes/Covers issue

Fixes #

[Copilot]

Pull Request Overview

This PR replaces the JavaScript-based onboarding modal with a TypeScript implementation, improving type safety and modernizing the codebase. The changes also relocate asset enqueueing logic and use the WordPress Settings API with proper nonces for better security.

Key Changes

• Complete TypeScript rewrite of the onboarding modal with proper type definitions
• Migration from custom API endpoints to WordPress Settings API (/wp/v2/settings)
• Asset enqueueing colocated with component logic in Admin.php instead of centralized in Assets.php

Reviewed Changes

Copilot reviewed 12 out of 14 changed files in this pull request and generated 13 comments.

Show a summary per file

File	Description
webpack.config.js	Updated entry point from plugin/index.js to onboarding/index.tsx
tsconfig.json	Added TypeScript configuration with strict type checking enabled
package.json	Added TypeScript, React types, and @wordpress/api-fetch dependencies; added type checking script
package-lock.json	Updated lockfile with new dependencies and version bumps
inc/Modules/Settings/Settings.php	Changed sanitization callback to return empty string instead of null for invalid site types
inc/Modules/Settings/Admin.php	Added enqueue_scripts and enqueue_onboarding_scripts methods to handle onboarding asset loading
inc/Modules/Core/Assets.php	Renamed PLUGIN_SCRIPT_HANDLE to ONBOARDING_SCRIPT_HANDLE and registered onboarding styles; removed old plugin script enqueueing logic
assets/src/css/onboarding.scss	New stylesheet for onboarding modal with modal positioning and styling
assets/src/css/admin.scss	Moved onboarding-specific styles to dedicated onboarding.scss file; minor formatting update
assets/src/admin/plugin/index.js	Deleted old JavaScript implementation
assets/src/admin/onboarding/page.tsx	New TypeScript component for onboarding screen using apiFetch and Settings API
assets/src/admin/onboarding/index.tsx	New entry point with global type definitions for localized script data
.eslintrc.json	Updated ESLint config with TypeScript support and additional plugins
.eslintrc	Removed old ESLint config file (replaced by .eslintrc.json)

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[Copilot]

Pull Request Overview

Copilot reviewed 15 out of 17 changed files in this pull request and generated 2 comments.

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