Checked fields, capture metrics, thresholds, upload limits

What GET .../info publishes: what a caller can send and read.

Everything describing how the gate is built — which artifacts are loaded, whether a reader is installed, how each capture metric is weighted — was here and is not any more. It told a caller nothing they could act on and told anyone else how the catalogue is assembled. Operators still get all of it from Service.diagnostics(), which /readyz reports and no key can reach.