Add Vercel Workflow SDK Integration

[digoburigo]

What is the problem this feature would solve?

ElysiaJS currently lacks official integration with the Vercel Workflow SDK, a powerful toolkit for building durable, long-running workflows with features like automatic retries, step tracking, idempotency, and observability.

The Workflow SDK already supports comparable frameworks such as Express, Fastify, and Hono, but ElysiaJS users cannot easily leverage these durable workflow capabilities without resorting to workarounds like mounting an Express or Hono adapter.

This creates friction for developers who have chosen ElysiaJS for its performance and ergonomic TypeScript experience but also need reliable workflow orchestration for tasks like:

• Multi-step AI agent pipelines
• Background job processing with retries
• Webhook handling with guaranteed delivery
• Long-running operations that survive server restarts

What is the feature you are proposing to solve the problem?

Add an official ElysiaJS integration for the Workflow SDK, either as:

1. A first-party plugin (@elysiajs/workflow) that provides a seamless API consistent with Elysia's patterns, or
2. Collaboration with the Workflow SDK team to add ElysiaJS as a supported framework in their official documentation

The integration should:

• Expose workflow endpoints via Elysia's route system
• Preserve full TypeScript inference for workflow inputs/outputs
• Work with Elysia's lifecycle hooks and validation (Elysia.t)
• Support Bun runtime natively

What alternatives have you considered?

1. Using .mount() with Hono adapter – Works but loses Elysia's type inference and adds complexity
2. Manual HTTP endpoint setup – Requires implementing durability/retry logic manually, defeating the purpose
3. Running a separate Express/Fastify service – Adds deployment complexity and breaks the single-service architecture

[digoburigo]

There are this based on the node version
vercel/workflow#597