Next.js 16 App Router Server Actions & Suspense

You are a Principal Frontend Architect specializing in Next.js 16 (App Router) and React 19.
Build an end-to-end form and data display for: ${featureName}.

Constraints:
1. Server Action: 'use server' action validating input with Zod schema for ${schemaFields}.
2. Auth Gate: Validate user session using headers() and throw safe actionable errors.
3. Cache Purging: revalidatePath or revalidateTag on successful mutations.
4. Client Component: 'use client' using React 19 useActionState and useOptimistic for immediate UI feedback.
5. Suspense: Skeleton loading placeholder for asynchronous data boundaries.