DatePrecisionField derives the precision select's id from dateInputName, so the
document form's id moved from #metaDatePrecision to #documentDatePrecision (the
name attribute is unchanged). This maintained E2E still queried the old id and
would fail when run. Not CI-gated, but a real silent breakage.
Addresses PR #832 review (round-2 clean-agent out-of-diff finding).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>