Task: Migrate a Third-Party SDK Integration to Effect

You are working on a backend service that interacts with a document storage SDK. The current implementation uses raw async/await and scatters Promise conversions throughout the codebase. Your job is to migrate the integration to idiomatic Effect TypeScript.

Project Context

The project is at /workspace/scenario-3-project/. It has effect and @effect/platform-node installed. The existing code lives in src/storage/.

The SDK (DocumentStoreClient) has many operations (upload, download, delete, list, getMetadata, setMetadata, createFolder, etc.) and each returns a Promise. The SDK also accepts an optional AbortSignal on each call.

The existing file src/storage/legacy.ts shows the current async/await implementation (read it for context on how the SDK is used and what errors it throws).

What to Produce

Write the following new files:

• /workspace/scenario-3-project/src/storage/DocumentStore.ts — the Effect service wrapping the SDK
• /workspace/scenario-3-project/src/storage/errors.ts — typed error definitions for SDK failures
• /workspace/scenario-3-project/src/storage/index.ts — barrel export

Additionally, in /workspace/scenario-3-project/src/app.ts, there is a React-like framework callback that needs to call Effect code. Update it to use a runtime approach appropriate for a non-Effect host environment executing Effect code repeatedly.

Constraints

• The service must handle the wide SDK surface without manually wrapping every method
• Cancellation must be preserved using AbortSignal where the SDK supports it
• All SDK errors must be converted to a typed tagged error rather than left as unknown
• Do not call any Effect.run* inside the DocumentStore service itself
• The app.ts framework callback should not be refactored into a full Effect entrypoint — the surrounding framework code must remain as-is
• Write idiomatic TypeScript