Line number int (#11885)

* Add migration

Co-authored-by: Copilot <copilot@github.com>

* Update model on save

Co-authored-by: Copilot <copilot@github.com>

* Add API filter aliases

Co-authored-by: Copilot <copilot@github.com>

* Improved query for data migration

Co-authored-by: Copilot <copilot@github.com>

---------

Co-authored-by: Copilot <copilot@github.com>

src/backend/InvenTree/order/models.py

@@ -1755,6 +1755,8 @@ class OrderLineItem(InvenTree.models.InvenTreeMetadataModel):
 
     Attributes:
         quantity: Number of items
+        line: The line number for this item (optional)
+        line_int: An integer line number for this item (optional - used for natural sorting)
         reference: Reference text (e.g. customer reference) for this line item
         project_code: Project code associated with this line item (optional)
         note: Annotation for the item
@@ -1778,6 +1780,15 @@ class OrderLineItem(InvenTree.models.InvenTreeMetadataModel):
 
         update_order = kwargs.pop('update_order', True)
 
+        # Update the integer representation of the line number (for natural sorting)
+        if self.line:
+            try:
+                self.line_int = int(self.line)
+            except (TypeError, ValueError):
+                self.line_int = 0
+        else:
+            self.line_int = 0
+
         super().save(*args, **kwargs)
         if update_order and self.order:
             self.order.save()
@@ -1819,6 +1830,8 @@ class OrderLineItem(InvenTree.models.InvenTreeMetadataModel):
         help_text=_('Line number for this item (optional)'),
     )
 
+    line_int = models.IntegerField(default=0, blank=False, null=False)
+
     reference = models.CharField(
         max_length=100,
         blank=True,