Fusion Help Integration

Wires the Fusion Help Center into your app pages by creating article slug constants, adding the useHelpCenter hook, and connecting PageLayout props so users can click the help button and open contextual articles. You'd reach for this when adding help support to pages that use PageLayout but don't have the openHelpArticle callback wired up yet. It handles the full integration pattern: constants file with slug mappings, hook destructuring, and the callback wrapper that trips people up. The main gotcha is that slugs must exactly match what's published via fhelp, so it confirms auto-derived names before applying them. Doesn't author the actual markdown articles or touch shared UI components, just connects the dots between your page and the help system.