Add new action skills for AL testing and documentation

- Introduced `al-test-writer` to generate AL test codeunits for production objects based on TDD principles.
- Added `al-userguide-test-writer` to create test codeunits from user guide steps, mapping actions and assertions.
- Implemented `bc-extension-test-guide` to generate a comprehensive TEST_GUIDE.md for Business Central extensions, covering various categories.
- Created `bc-webclient-runner` to automate UI testing of the Business Central web client, capturing screenshots and asserting UI states.
- Developed `page-scripting-e2e` to produce a recording plan for Page Scripting, ensuring a structured approach to browser-level testing.

custom/knowledge/integration/prefer-business-events-over-handwritten-retry-loops.bad.al

@@ -0,0 +1,35 @@
+// Anti-pattern: a hand-written HTTP retry loop for a fire-and-forget notification. It
+// reimplements platform retry, backoff, and durability (usually less correctly), couples
+// delivery to BC staying up for the life of the loop, and runs inline on the caller's thread.
+
+codeunit 50162 "Shipment Notifier Bad"
+{
+    procedure NotifyShipmentReleased(DocumentNo: Code[20])
+    var
+        Client: HttpClient;
+        Content: HttpContent;
+        Response: HttpResponseMessage;
+        Attempt: Integer;
+    begin
+        Content.WriteFrom(BuildJson(DocumentNo));
+
+        // BAD: a hand-rolled retry loop for a one-way notification an external business event
+        // would carry. Everything in this loop is something the platform already does for free.
+        for Attempt := 1 to 5 do begin
+            if Client.Post('https://wms.contoso.com/api/events', Content, Response) then
+                // BAD: status classification by hand. A real implementation must distinguish
+                // 408/429/5xx (retry) from 4xx (give up), and this one does not even try.
+                if Response.IsSuccessStatusCode() then
+                    exit;
+
+            // BAD: hand-rolled backoff. The platform's external-event delivery already retries
+            // with backoff for up to ~36 hours and persists the state across restarts.
+            Sleep(Attempt * 2000);
+        end;
+
+        // BAD: the loop lives entirely in this session. If the WMS is DOWN for the whole window
+        // the notification is lost; and if BC RESTARTS mid-loop, the retry state is gone and the
+        // notification is silently lost with no record that it was ever attempted. Nobody is
+        // alerted, so the gap is found only when downstream is discovered to be out of sync.
+    end;
+}