Output Qt Designer file

Inspect a `Binder` hierarchy and write it out as a Qt Designer `.ui` file so you can prototype the `Binder` using the simple declarative syntax, then tweak it quickly to look excellent for production.

The issue names no files, tests, or entry points. Start by locating the Binder hierarchy implementation and existing Qt widget serialization or export code, then define the expected .ui output and a test or example that demonstrates a Binder hierarchy can be written and reopened by Qt Designer.

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