Support multi-page PDFs for more than 3 selected checks

- pdfService: batch checks into groups of 3, add doc.addPage() between groups
- pdf route: remove 1-3 limit, accept any number of check IDs
- Frontend: remove 3-check selection cap; any number of checks can be selected

public/js/app.js

@@ -70,7 +70,6 @@ function renderTable() {
 
   tbody.innerHTML = checks.map(renderRow).join('');
   updateSortIndicators();
-  updateCheckboxStates();
 
   // Attach row-level event listeners
   tbody.querySelectorAll('input[type="checkbox"]').forEach(cb => {
@@ -157,14 +156,6 @@ function updateSortIndicators() {
   });
 }
 
-function updateCheckboxStates() {
-  document.querySelectorAll('#checks-tbody input[type="checkbox"]').forEach(cb => {
-    const id = parseInt(cb.dataset.id, 10);
-    if (!state.selected.has(id)) {
-      cb.disabled = state.selected.size >= 3;
-    }
-  });
-}
 
 function refreshPdfButton() {
   const n = state.selected.size;
@@ -178,16 +169,11 @@ function refreshPdfButton() {
 function onCheckboxChange(cb) {
   const id = parseInt(cb.dataset.id, 10);
   if (cb.checked) {
-    if (state.selected.size >= 3) {
-      cb.checked = false;
-      return;
-    }
     state.selected.add(id);
   } else {
     state.selected.delete(id);
   }
   refreshPdfButton();
-  updateCheckboxStates();
 }
 
 // ── Slide-in panel ───────────────────────────────────────────────────────────
@@ -298,7 +284,7 @@ async function deleteCheck(id) {
 
 async function generatePdf() {
   const ids = [...state.selected];
-  if (ids.length === 0 || ids.length > 3) return;
+  if (ids.length === 0) return;
 
   const btn = document.getElementById('btn-generate-pdf');
   btn.disabled = true;

src/routes/pdf.js

@@ -17,8 +17,8 @@ const { generateCheckPdf } = require('../services/pdfService');
 router.post('/', async (req, res) => {
   const { checkIds } = req.body;
 
-  if (!Array.isArray(checkIds) || checkIds.length === 0 || checkIds.length > 3) {
-    return res.status(400).json({ error: 'checkIds must be an array of 1–3 IDs' });
+  if (!Array.isArray(checkIds) || checkIds.length === 0) {
+    return res.status(400).json({ error: 'checkIds must be a non-empty array' });
   }
 
   // Fetch account

src/services/pdfService.js

@@ -88,7 +88,7 @@ function formatMicrLine(routingNo, accountNo, checkNo) {
 }
 
 /**
- * Main export: generates a PDF buffer for 1–3 checks.
+ * Main export: generates a multi-page PDF buffer for any number of checks (3 per page).
  *
  * @param {Object} account - Account row from database
  * @param {Array}  checks  - Array of 1–3 check rows from database
@@ -128,14 +128,17 @@ function generateCheckPdf(account, checks, fields) {
     const hasUsableLogo = !!(logoField && account.logo_data);
     const COMPANY_FIELDS = new Set(['Company Name', 'Company Name2', 'Company Name3', 'Company Name4']);
 
-    // We always render 3 slots; empty slots get a blank placeholder
-    for (let slot = 0; slot < 3; slot++) {
-      const check = checks[slot] || null;
-      const slotOriginY = slot * SLOT_HEIGHT_IN;
+    const offX = (account.offset_right - account.offset_left);
+    const offY = (account.offset_down - account.offset_up);
 
-      // Offset adjustments from account calibration
-      const offX = (account.offset_right - account.offset_left);
-      const offY = (account.offset_down - account.offset_up);
+    // Render checks in pages of 3; add a new page for each additional group
+    const pages = Math.ceil(checks.length / 3);
+    for (let page = 0; page < pages; page++) {
+      if (page > 0) doc.addPage();
+
+      for (let slot = 0; slot < 3; slot++) {
+      const check = checks[page * 3 + slot] || null;
+      const slotOriginY = slot * SLOT_HEIGHT_IN;
 
       // Helper: convert inches (relative to slot) to PDF points (absolute page)
       const pt = (xIn, yIn) => ({
@@ -220,7 +223,8 @@ function generateCheckPdf(account, checks, fields) {
            .text(micrLine, micrPos.x, micrPos.y, { lineBreak: false });
       }
 
-    }
+      } // end slot loop
+    } // end page loop
 
     doc.end();
   });