feat(subscription): QR credentials — operator-choose (QR-only now), auto-generate, multi-month, printed card

Builds out subscription credentials on top of the rename.

- Operator chooses the credential type; only QR is live (RFID shown disabled
  "soon"). Backend/schema keep accepting both — re-enabling RFID is UI-only.
- QR codes are AUTO-GENERATED server-side (SUB-<base32>, crypto-random,
  globally-unique-checked) — the customer/operator never picks the value.
  RF stays operator-entered (the physical card id). Reader output decided =
  TCP/IP full string (Wiegand-numeric fallback noted).
- Multi-month: form takes a `months` count → server sets validTo =
  validFrom + N months (day-clamp); one record/one window; total = N×monthly.
- The QR card is PRINTED so the operator can hand it over: real ESC/POS 2D QR
  (GS ( k) added to the Rongta driver (printSubscriptionCard); auto-print on
  create (best-effort — never fails the create; returns {printed,printError})
  + reprint via POST /api/subscriptions/:id/print and a "Print code" button.

Verified via buildServer+inject incl. a TCP capture of the on-wire QR bytes
(autogen+uniqueness, Jan31+3mo→Apr30, auto-print, GS ( k QR with embedded
code, reprint, no-QR→409). Updated wiki (subscription, rongta-printer). No
migration.

Claude-Session: https://claude.ai/code/session_01Xcm6ikLgGoCxxHrxtjkk5V

apps/server/src/booth-print.ts

@@ -79,3 +79,29 @@ export async function printExitVoucher(
   logger.info(`exit voucher for ${ticketId} printed on ${printedBy}`);
   return printedBy;
 }
+
+/**
+ * Print a SUBSCRIPTION CARD on the booth printer (failing over to the dispenser):
+ * a scannable QR of the credential code + holder/validity, so the operator can hand
+ * it to the customer. Used on subscription creation and on a "reprint" action.
+ * Returns the printer that printed it; throws NoPrinterAvailableError if none can.
+ */
+export async function printSubscriptionCard(
+  db: Db,
+  card: { code: string; holderName?: string | null; validFrom?: string | null; validTo?: string | null },
+  logger: FastifyBaseLogger,
+): Promise<string> {
+  const printers = loadPrinters(db);
+  const data = {
+    code: card.code,
+    holderName: card.holderName ?? null,
+    validFrom: card.validFrom ?? null,
+    validTo: card.validTo ?? null,
+    header: ticketHeader(db),
+  };
+  const printedBy = await printWithFailover(printers, "booth-receipt", (d: PrinterDevice) =>
+    d.printSubscriptionCard(data),
+  );
+  logger.info(`subscription card ${card.code} printed on ${printedBy}`);
+  return printedBy;
+}