Description

formatServerError in packages/app/src/utils/server-errors.ts handles Error, strings, and typed config/model errors, but plain objects from the API often fall through to "Unknown error".

Example payloads that should display a useful message:

• { data: { message: "Sidecar unavailable" } }
• { message: "Connection refused" }
• { name: "ServerTimeoutError", data: { seconds: 30 } }

This shows up in desktop/web UI error toasts when the sidecar returns structured JSON instead of an Error instance.

Steps to reproduce

1. Surface an API error object with data.message (not an Error instance) to formatServerError.
2. Observe "Unknown error" instead of the message field.

Operating System

Any (app package)