Add a /reports page built on react-openapi's runtime configs:
- inline generate panel (GroupSpec enum, prefetched payee picker,
strict DD-MM-YYYY range, 400 surfacing)
- metadata report list with view/regenerate/delete
- viewer that slices the cached per-entity payload via
metadata.group_options, aggregates metrics + txns, pivots
period x payee, and renders month accordions
- route + nav entry; no hand-rolled schema duplication