Fix cart item lookup to use orderLineItemId directly

- Add IsDeleted=0 filter to existing item search query
- Add support for OrderLineItemID parameter for direct item targeting
- Fixes duplicate items being created on quantity increment
- Fixes item deletion not working due to finding wrong/deleted records

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

api/orders/setLineItem.cfm

@@ -288,6 +288,7 @@
 
 <cfset OrderID = val( structKeyExists(data,"OrderID") ? data.OrderID : 0 )>
 <cfset ParentLineItemID = val( structKeyExists(data,"ParentOrderLineItemID") ? data.ParentOrderLineItemID : 0 )>
+<cfset OrderLineItemID = val( structKeyExists(data,"OrderLineItemID") ? data.OrderLineItemID : 0 )>
 <cfset OriginalItemID = structKeyExists(data,"ItemID") ? data.ItemID : 0>
 <cfset ItemID = val(OriginalItemID)>
 
@@ -399,10 +400,27 @@
     </cfif>
   </cfif>
 
-  <!--- Find existing line item (by order, parent LI, item) - unless ForceNew is set --->
+  <!--- Find existing line item - by direct ID if provided, otherwise by order/parent/item --->
   <cfif ForceNew>
     <!--- ForceNew: Skip existing lookup, will always create new line item --->
     <cfset qExisting = queryNew("ID", "integer")>
+  <cfelseif OrderLineItemID GT 0>
+    <!--- Direct lookup by OrderLineItemID --->
+    <cfset qExisting = queryTimed(
+      "
+        SELECT ID
+        FROM OrderLineItems
+        WHERE ID = ?
+          AND OrderID = ?
+          AND IsDeleted = 0
+        LIMIT 1
+      ",
+      [
+        { value = OrderLineItemID, cfsqltype = "cf_sql_integer" },
+        { value = OrderID, cfsqltype = "cf_sql_integer" }
+      ],
+      { datasource = "payfrit" }
+    )>
   <cfelse>
     <cfset qExisting = queryTimed(
       "
@@ -411,6 +429,7 @@
         WHERE OrderID = ?
           AND ParentOrderLineItemID = ?
           AND ItemID = ?
+          AND IsDeleted = 0
         LIMIT 1
       ",
       [