Add 18 community AL/BC patterns across style, data-modeling, web-services, appsource, breaking-changes, performance, and testing

Contributed by CURABIS ApS, generalized from patterns observed across real AppSource/PTE development. Each article follows the knowledge file format (frontmatter, Description/Best Practice/Anti Pattern, sibling .good.al/.bad.al samples).

microsoft/knowledge/style/var-parameters-require-an-addressable-variable.good.al

@@ -0,0 +1,17 @@
+codeunit 50100 "Customer Lookup"
+{
+    procedure GetCustomerName(CustomerNo: Code[20]; var Name: Text[100])
+    var
+        Customer: Record Customer;
+    begin
+        if Customer.Get(CustomerNo) then
+            Name := Customer.Name;
+    end;
+
+    procedure Sample()
+    var
+        CustName: Text[100];
+    begin
+        GetCustomerName('10000', CustName);
+    end;
+}