fix(pdf): correct multi-page invoice/quote layout + drop IBAN dup under Swiss QR

Before drawing the line-items table, the renderer inflated page 1's bottom
margin to reserve room for the bottom-pinned totals block, but the `finally`
restored it on whichever page the table *ended* on — leaving page 1
permanently short on any multi-page document. On long invoices and quotes
this caused:

  - the table to break far too early (only ~6 items on page 1, large blank
    gap beneath)
  - the page-number stamp to land below page 1's phantom bottom margin,
    auto-paginating a stray blank trailing page and desyncing the
    "Seite X von Y" labels (page 1 unnumbered, the blank page labelled
    "Seite 1 von N")

Let the table paginate with the document's normal margins so each page fills
to the bottom; the existing desiredTotalsY check already advances to a fresh
page when the last item row would collide with the pinned totals block.

Also suppress the IBAN block under the totals when a Swiss QR-bill slip is
appended: the slip already prints the account/IBAN in human-readable form,
so it was pure duplication. The EPC QR path keeps the block (its QR lives on
a trailing page, so on-page bank details still help).

backend/src/services/pdfService.js

@@ -916,7 +916,14 @@ function drawPaymentBlock(doc, ctx, x, y, width) {
   const showSkontoHere = isQuote
     ? (issuer?.quoteShowSkonto !== false)
     : reminderLevel === 0;
-  const showIbanHere    = !isQuote;
+  // Invoices show the IBAN block in the right column EXCEPT when a
+  // Swiss QR-bill slip is appended: that slip already prints the
+  // account/IBAN ("Konto / Zahlbar an") in human-readable form, so
+  // repeating "Der Betrag ist auf die folgende Bankverbindung zu
+  // überweisen: …" under the totals is pure duplication. The EPC QR
+  // path keeps the block — its QR lives on a trailing page, so having
+  // the bank details on the invoice page itself still helps.
+  const showIbanHere    = !isQuote && ctx.qrFormat !== 'swiss';
 
   // If the quote has nothing to print in either column, bail out
   // early — don't render a bare "Payment conditions:" header with
@@ -1610,29 +1617,25 @@ function renderDocument(type, context) {
       doc.y = y;
       doc.x = leftX;
 
-      // Force the items table to auto-paginate BEFORE it can collide
-      // with the totals + payment block at the page bottom. We
-      // compute the same anchor as below, then temporarily inflate
-      // the page's bottom margin so swissqrbill's Table sees a
-      // shorter usable area and breaks to a new page when items
-      // would otherwise spill into the totals zone. The header row
-      // is already marked `header: true` so it auto-repeats on the
-      // continuation page.
-      const _origBottomMargin = doc.page.margins.bottom;
-      const _itemsBottomReserve = PAGE.marginBottom
-        + 30                                  // FOOTER_RESERVE
-        + (ctx.paymentTerm ? 80 : 50)         // PAYMENT_BLOCK_HEIGHT
-        + 12                                  // gap between totals + payment
-        + 90                                  // TOTALS_BLOCK_HEIGHT
-        + 20;                                 // small breathing room
-      doc.page.margins.bottom = _itemsBottomReserve;
-      try {
-        drawLineItems(doc, ctx);
-      } finally {
-        // Restore even if drawLineItems threw — keeps subsequent
-        // pages on the document's normal margin geometry.
-        doc.page.margins.bottom = _origBottomMargin;
-      }
+      // Let the items table paginate with the document's NORMAL
+      // margins so each page fills to the bottom. The header row is
+      // marked `header: true` so it auto-repeats on every
+      // continuation page. Totals/payment placement is handled below:
+      // they're pinned to a fixed anchor near the page bottom, and if
+      // the last item row spilled past that anchor we advance to a
+      // fresh page before drawing them (see the desiredTotalsY check).
+      //
+      // We deliberately do NOT inflate the bottom margin here to
+      // "reserve" the totals zone on every page. That older approach
+      // shortened the usable area on EVERY page (not just the last),
+      // so a long invoice broke far too early — only a handful of
+      // line items rendered on page 1 with a large blank gap beneath.
+      // Worse, the inflated margin was set on the page active when the
+      // table started but restored on whichever page the table ended,
+      // leaving page 1 permanently short: the page-number stamp later
+      // landed below that page's phantom bottom margin and spawned a
+      // stray blank trailing page (which then desynced "Seite X von Y").
+      drawLineItems(doc, ctx);
       // y after the table — used only to detect whether the items
       // overflowed past the totals anchor below. We don't use it as
       // the totals position directly because the totals block is