Mental-model reset for SvelteKit apps. Use when writing or reviewing routes, layouts, load functions, form actions, remote functions, hooks, auth, cookies, endpoints, redirects, errors, SSR, progressive enhancement, or app-level data flow. Triggers on SvelteKit, +page, +layout, +server, +page.server.ts, +layout.server.ts, hooks.server.ts, load, actions, fail(), redirect(), error(), cookies, locals, route groups, protected routes, sessions, form actions, enhance, remote functions, command(), query(), form(), getRequestEvent(), SSR, hydration, and serialization. Use svelte5 for component-level runes, snippets, accessibility, actions, transitions, and component API review.