[Grace256c]

What & Why

Fixes synk user list reporting a successful response as an API error.

The Synkronus GET /api/users handler returned a valid JSON array but did not set Content-Type: application/json. The generated CLI client only parses the HTTP 200 response into JSON200 when the response content type is JSON, so the successful response was left unparsed and treated as an API error.

This PR updates the server handler to return the correct JSON content type and adds regression coverage for both the server response and the CLI client parsing path.

Closes #1021.

Type of Change

• Bug fix
• New feature / enhancement
• Refactor / cleanup
• Documentation
• Chore / other

Component(s) Changed

• formulus (React Native mobile app)
• formulus-formplayer (form WebView UI)
• synkronus (Go backend)
• synkronus-cli (command-line client)
• synkronus-portal (web admin UI)
• desktop (Tauri app)
• packages (tokens / components)
• Documentation / DevOps / CI

Testing

• Added/updated tests
• Manually tested
• Not applicable

Checklist

• Pre-flight checks for changed packages passed (lint / format / tests)
• Breaking changes (if any) have migration steps
• Related issue linked: Closes [synkronus-cli] synk user list reports a successful response as an error #1021