feat(statements): OCR intake for scanned utility bills

Staff key 300+ utility statements per company per month by hand. This adds
the ingest -> split -> OCR -> match -> review pipeline that proposes customer
and amount per page instead (RECEIPT_CAPTURE_SPEC §2), posting through the
existing BillingService.createBatch seam with source=OCR and a per-document
captureRef so machine and hand capture share one write path and audit trail.

Everything was designed against 10 real scanned statements (46 pages of CFE,
CESPT and Telnor bills) rather than from the sample-free spec. The scans have
no text layer at all — they are camera images — so OCR is mandatory, and they
arrive bundled one customer per page. Measured on those pages the parser
identifies the provider 46/46 and reads an account reference 43/46; against
the dev database that is 39/46 (85%) exact auto-match, 40/46 identified, with
the rest genuine review cases. That closes the OCR-provider question in favour
of self-hosted Tesseract: it clears the bar for a queue where a human confirms
every row, and OcrProvider keeps a managed API a one-line swap.

The samples corrected three things the spec had wrong or unknown:

- Clave catastral is NOT predial. DATMEX.clave (934 rows) is what CESPT and
  predial bills print; DATMEX.predial, which PROPERTY_TAX.accountNumber holds,
  has 663 distinct values across 1135 rows and appears on no statement. The
  clave now lives on Property.cadastralKey as the matcher's secondary key;
  predial is left untouched. This had been blocking predial matching.
- Gas was recoverable: 160 of 334 DATMEX.gas values are real account numbers
  (the rest are ESTACIONARIO/CILINDRO descriptors), now in GAS.meterNumber.
- Phone is one billed line per property (534/18/1 across phone1/2/3), so the
  new TELEPHONE ServiceKind backfills from phone1 only, not three rows.

Matching is scoped to one column per service kind and never reads the customer
name — a CESPT receipt prints ARNAIZ ROSAS ELSA AURORA for an account this
office holds under CATT, RANDY, because the printed name is the registrant,
not the current owner. Where a provider prints a payment barcode it beats the
printed label (one CFE label OCR'd a digit too many while its barcode was
correct) and the two cross-check, with disagreement forcing review.

Confirming a document whose service had no reference writes it back, so gas
and any other cold start is a one-time cost rather than a permanent queue.

Verified end to end against the live dev API and MinIO: real scans uploaded
over HTTP, matched, confirmed against a check, and the resulting rows checked
in MySQL (negative amounts, captureSource=OCR, concept derived from the batch
kind, captureRef linking back to each page). Re-confirming a posted batch is
refused. Test data was removed afterwards.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docker/api.Dockerfile

@@ -46,7 +46,17 @@ ENV NODE_ENV=production
 #   ERROR 1045: Plugin caching_sha2_password could not be loaded
 # That breaks the pre-migrate deploy backup AND the whole "Operaciones" admin
 # panel (backup, restore, sync, re-import all shell out to these binaries).
+#
+# tesseract-ocr + tesseract-ocr-data-spa + poppler-utils drive the statement
+# OCR intake (RECEIPT_CAPTURE_SPEC §2): poppler's `pdftoppm` rasterises each
+# scanned page and tesseract reads it, with the Spanish traineddata for the
+# accented labels on CFE/CESPT/Telnor bills. These are external binaries rather
+# than a native npm addon so the pnpm workspace stays free of a compiled
+# dependency. If they are absent the API still boots — the statements module
+# reports itself unavailable and only that feature is disabled — but statement
+# ingest is the point of shipping them.
 RUN apk add --no-cache python3 mdbtools mysql-client mariadb-connector-c openssl \
+      tesseract-ocr tesseract-ocr-data-spa poppler-utils \
  && apk add --no-cache --virtual .pybuild python3-dev build-base \
  && rm -rf /var/cache/apk/*