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/setup-table-is-a-singleton.good.al

@@ -0,0 +1,70 @@
+table 50364 "Loyalty Setup"
+{
+    Caption = 'Loyalty Setup';
+    DataClassification = CustomerContent;
+
+    fields
+    {
+        field(1; "Primary Key"; Code[10])
+        {
+            Caption = 'Primary Key';
+        }
+        field(10; "Member Nos."; Code[20])
+        {
+            Caption = 'Member Nos.';
+            TableRelation = "No. Series";
+        }
+    }
+
+    keys
+    {
+        key(PK; "Primary Key")
+        {
+            Clustered = true;
+        }
+    }
+
+    procedure GetRecordOnce()
+    begin
+        if Rec.Get() then
+            exit;
+        Rec.Init();
+        Rec.Insert();
+    end;
+}
+
+page 50365 "Loyalty Setup"
+{
+    Caption = 'Loyalty Setup';
+    PageType = Card;
+    SourceTable = "Loyalty Setup";
+    UsageCategory = Administration;
+    ApplicationArea = All;
+    InsertAllowed = false;
+    DeleteAllowed = false;
+
+    layout
+    {
+        area(Content)
+        {
+            group(Numbering)
+            {
+                Caption = 'Numbering';
+                field("Member Nos."; Rec."Member Nos.")
+                {
+                    ApplicationArea = All;
+                    ToolTip = 'Specifies the number series used to assign member numbers.';
+                }
+            }
+        }
+    }
+
+    trigger OnOpenPage()
+    begin
+        Rec.Reset();
+        if not Rec.Get() then begin
+            Rec.Init();
+            Rec.Insert();
+        end;
+    end;
+}