feat(ui): add full control JSON editing and create-from-JSON

[lan17]

Summary

• add Full JSON mode for editing the entire control definition from the control modal
• add From JSON in the create-control flow so a control can be created directly from JSON without picking an evaluator first
• reuse a shared JSON editor for both full control definitions and evaluator config JSON
• add helper text clarifying that the control JSON editor expects the raw control definition, not data / name / id wrapper objects
• add Playwright coverage for the JSON create/edit flows

Testing

• make ui-typecheck
• make ui-lint (passes; existing no-img-element warnings remain in ui/src/core/layouts/app-layout.tsx)

Screenshots

New control UI now has From JSON button`

When you click on it you get this

you can also edit full json in control now

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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