feat(community/agents): add AL agent quality guidance

- add 20 agent knowledge rules with good and bad AL samples
- clarify setup dialog shape, temporary persistence, permissions, profiles, instructions, capability registration, and interface wiring
- add the community-owned AL agents review skill
- make review fixture discovery layer-aware with custom, community, and Microsoft precedence
- document layer-aware evaluation behavior

community/knowledge/agents/instructions-describe-work-not-tool-ids.good.al

@@ -0,0 +1,12 @@
+codeunit 50100 "Sales Review Agent Instr."
+{
+    procedure GetInstructions() Instructions: SecretText
+    var
+        Builder: TextBuilder;
+    begin
+        Builder.AppendLine('Memorize the sales order number from the task.');
+        Builder.AppendLine('Set the order on hold when credit fails, with a reason.');
+        Builder.AppendLine('When credit passes, request a review before posting the order.');
+        Instructions := Builder.ToText();
+    end;
+}