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/get-default-profile-lives-in-the-app.bad.al

@@ -0,0 +1,9 @@
+codeunit 50100 "Sales Review Agent Factory"
+{
+    procedure GetDefaultProfile(var TempAllProfile: Record "All Profile" temporary)
+    begin
+        // Profile exists only as a user personalization in the design sandbox.
+        TempAllProfile."Profile ID" := 'SALES REVIEW SANDBOX';
+        TempAllProfile.Insert();
+    end;
+}