Design for replacing _translate.py/_dates.py with whoosh-compat: shared
field-definition table driving both the Tantivy schema and the query
FieldRegistry, diagnostics->exception mapping (aggregating all errors,
not just the first), a 4-PR stack with no rollout flag, and a
result-level acceptance corpus + date-grammar parity audit as the
safety net instead.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
