Explain the point to whoever opens the admin

The overview leads with what Logbuch is for, a new Anleitung page renders
the editorial guide for humans, and the user list stops claiming accounts
come from a shell command: they appear on first sign in.

src/lib/admin-routes.ts

@@ -11,6 +11,7 @@ export const adminUsersPath = '/admin/users' as Route
 export const adminClientsPath = '/admin/clients' as Route
 export const adminPostTypesPath = '/admin/post-types' as Route
 export const adminSettingsPath = '/admin/settings' as Route
+export const adminGuidePath = '/admin/guide' as Route
 export const adminNewPostTypePath = '/admin/post-types/new' as Route
 
 export function adminApiFilePath(file: 'openapi' | 'style-guide' | 'skill'): Route {