Improve FG scan page UX and integrate scan-to-boxes with QZ Tray printing

- Redesigned scan card layout: 500px width with horizontal label-input layout
- Reduced spacing and optimized for no scrolling (700px max-height)
- Added auto-advance between fields when valid data is entered
- Integrated scan-to-boxes popup with warehouse box assignment
- Added QZ Tray printing to Quick Box Creation button
- Box labels now print automatically after creation in scan workflow
- Fixed warehouse blueprint URL prefix registration (/warehouse)
- Updated manage_boxes to return JSON for AJAX requests
- Improved error message grid layout to maintain form alignment

py_app/app/static/css/scan.css

@@ -1,30 +1,48 @@
 /* Scan Module Specific Styles */
 
 .scan-form-card {
-    width: 380px;
-    max-width: 380px;
+    width: 500px;
+    max-width: 500px;
     margin: 0 auto 20px auto;
-    max-height: 660px;
+    max-height: 700px;
     overflow-y: auto;
-    padding: 18px 18px 12px 18px;
+    padding: 12px 18px 12px 18px;
+}
+
+.scan-form-card h3 {
+    margin-top: 0;
+    margin-bottom: 8px;
 }
 
 .scan-form-card form {
-    display: flex;
-    flex-direction: column;
-    gap: 4px;
+    display: grid;
+    grid-template-columns: 140px 1fr;
+    gap: 8px;
+    align-items: center;
 }
 
 .scan-form-card label {
     font-weight: 500;
-    margin-bottom: 1px;
+    margin-bottom: 0;
+    margin-top: 0;
     font-size: 13px;
+    text-align: left;
+    padding-right: 8px;
 }
 
 .scan-form-card input[type="text"] {
     padding: 5px 10px;
     font-size: 13px;
-    margin-bottom: 2px;
+    margin-bottom: 0;
+}
+
+.scan-form-card button[type="submit"],
+.scan-form-card button[type="button"] {
+    grid-column: 1 / -1;
+}
+
+.scan-form-card > form > div {
+    grid-column: 1 / -1;
 }
 
 .scan-table-card {