fix(frontend): replay row-flash on every refetch via dataUpdatedAt key

The previous static key={c.id} let React reuse the same <TableRow>
element across refetches, so animate-row-flash only played on
initial mount and on the first render of a brand-new claim_id.
Updated rows whose claim_id was unchanged never re-flashed.

Re-keying on `${c.id}-${dataUpdatedAt}` re-mounts the row on
every refetch (initial load, filter change, parse invalidation),
so the 1.2s accent-tint flash replays each time.

Also: README's 'Frontend unit tests (when added)' is stale — npm
test now exists and runs 3 passing tests.

hooks: add dataUpdatedAt: 0 to the !isConfigured fallback return
so the pages type-check.

src/hooks/useClaims.ts

@@ -54,6 +54,7 @@ export function useClaims(params: ListClaimsParams) {
       isError: false,
       error: null,
       refetch: () => Promise.resolve(),
+      dataUpdatedAt: 0,
     } as const;
   }
   return q;

src/hooks/useRemittances.ts

@@ -37,6 +37,7 @@ export function useRemittances(params: ListRemittancesParams) {
       isError: false,
       error: null,
       refetch: () => Promise.resolve(),
+      dataUpdatedAt: 0,
     } as const;
   }
   return q;