Adopt FieldLabel and FieldError across hand-rolled form labels and errors

Forms hand-roll `` elements (~87 occurrences across 42 files) and render errors without wiring them to their control, so labels focus nothing and screen readers announce nothing. Replace them with `FieldLabel`/`FieldError` in batches.

First pass: #8117 (the 15 `InputGroup component=` slot sites, which had zero wiring, plus CopyField and DateSelect label wiring). Remaining raw-label sites follow in batches, or as-touched.

Start with #8117 and inspect the 15 InputGroup component= slot sites, plus the CopyField and DateSelect label wiring mentioned in the issue. Compare those sites with the existing FieldLabel and FieldError components; done means the selected batch no longer hand-rolls labels or renders unassociated errors.

Written by the indexing model from the issue text.