Add data-modeling and appsource knowledge articles (MICROSOFT layer) (#65)

Author 7 remedial BCQuality knowledge articles plus good/bad AL samples
(21 files) covering AL master-table and data-model design:

- data-modeling: master No. from number series in OnInsert; use codeunit
  "No. Series" not obsolete NoSeriesManagement; setup table is a singleton;
  set Last Date Modified in OnModify and OnRename; enforce Blocked in
  referencing code not in the master.
- style: ApplicationArea required on page controls (AS0062).
- appsource: object affixes prevent collisions (AS0011).

Clean-room authored from own BC knowledge; specifics verified against public
sources only (learn.microsoft.com, microsoft/BCApps). Introduces two new
domains (data-modeling, appsource).

Co-authored-by: Jesper Schulz-Wedde <jesper.schulzwedde@microsoft.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

microsoft/knowledge/data-modeling/set-last-date-modified-in-onmodify-and-onrename.bad.al

@@ -0,0 +1,39 @@
+table 50369 "Loyalty Member"
+{
+    Caption = 'Loyalty Member';
+    DataClassification = CustomerContent;
+
+    fields
+    {
+        field(1; "No."; Code[20])
+        {
+            Caption = 'No.';
+        }
+        field(10; Name; Text[100])
+        {
+            Caption = 'Name';
+        }
+        field(20; "Last Date Modified"; Date)
+        {
+            Caption = 'Last Date Modified';
+            Editable = false;
+        }
+    }
+
+    keys
+    {
+        key(PK; "No.")
+        {
+            Clustered = true;
+        }
+    }
+
+    trigger OnModify()
+    begin
+        "Last Date Modified" := Today();
+    end;
+
+    // Missing OnRename: renaming the member changes the primary key without
+    // firing OnModify, so "Last Date Modified" keeps its old, stale value and
+    // change-detection logic downstream skips the renamed record.
+}