Wire the new ``?download=true`` resubmit endpoint into the Inbox
page. Operators can now ask the backend for a ZIP of regenerated
837s straight from the rejected-claims bulk action, with the
``X-Cyclone-Serialize-Errors`` header surfaced as a non-blocking
warning so partial successes don't swallow per-claim failures.
* ``src/lib/inbox-api.ts``: new ``resubmitRejectedWithDownload``
helper returning ``{blob, filename, serializeErrors}`` so callers
can hand the bundle to the new ``downloadBlob`` utility without
re-parsing headers.
* ``src/lib/download.ts``: new ``downloadBlob(blob, filename)`` plus
a test covering the extension/content-type mapping and the
"use the suggested filename when present" rule.
* ``src/pages/Inbox.tsx``: rejected-claims bulk action now exposes
a "Resubmit & download" button next to the existing JSON path,
wired through the helper. Conflicts and per-claim serialize
errors render in the existing toast/result surface.
Tests: 4 new download.ts tests, 5 inbox-api tests (including
serialize-errors header parsing).
Three pieces:
- src/lib/download.ts: generic downloadTextFile(filename, mime, text)
helper. Mirrors csv.ts:downloadCsv but takes an explicit MIME type and
drops the BOM prepend (which would corrupt the ISA segment).
- src/lib/api.ts: serializeClaim837(id) → {text, filename}. Fetches
GET /api/claims/{id}/serialize-837, pulls the suggested filename from
Content-Disposition (falls back to claim-{id}.x12 if the header is
missing). Throws ApiError on non-2xx so callers can branch on .status.
- ClaimDrawerHeader: Download icon button between the amount and the
close button. Click → api.serializeClaim837 → downloadTextFile.
Disabled + 'Downloading 837 file' aria-label while the fetch is in
flight so the click feels responsive. Optional onError prop surfaces
fetch failures; defaults to a no-op so existing callers stay clean.
Tests: 3 download.test.ts, 3 api.test.ts, 2 header.test.ts (happy
path + error path). Frontend: 350 passing (+8 from 342).