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/api/expose-bc-entities-as-api-pages-for-external-agents.bad.al

@@ -0,0 +1,60 @@
+// Anti-pattern: an unstable, over-broad agent surface. The version is not a
+// fixed contract, the entity is exposed through a part page the agent cannot
+// see, and every write is left open. Demonstration-only.
+
+// Smell 1: a ListPart can never surface as an agent tool. Only top-level API
+// pages are picked up, so this entity is silently unreachable.
+page 50121 "Agent Customer Part"
+{
+    PageType = ListPart;
+    SourceTable = Customer;
+
+    layout
+    {
+        area(Content)
+        {
+            repeater(Group)
+            {
+                field(no; Rec."No.") { }
+                field(name; Rec.Name) { }
+            }
+        }
+    }
+}
+
+// Smell 2: a top-level API page that is over-broad and unstable.
+page 50122 "Agent Vendor API"
+{
+    PageType = API;
+    SourceTable = Vendor;
+    APIPublisher = 'contoso';
+    APIGroup = 'purchasing';
+    // The version is bumped in place on each change instead of adding a new one,
+    // so every tool the agent discovered against v1.0 stops resolving.
+    APIVersion = 'v2.0';
+    EntityName = 'vendor';
+    EntitySetName = 'vendors';
+
+    // Nothing is locked down. A read-only agent workflow still gets create,
+    // modify, and delete tools, so a mistaken or prompt-injected agent can
+    // mutate or delete vendors it had no business touching.
+    // InsertAllowed / ModifyAllowed / DeleteAllowed left at permissive defaults.
+
+    layout
+    {
+        area(Content)
+        {
+            repeater(Group)
+            {
+                // The entire table sprayed out, far beyond what the agent needs,
+                // widening the schema and the write blast radius for no reason.
+                field(no; Rec."No.") { }
+                field(name; Rec.Name) { }
+                field(blocked; Rec.Blocked) { }
+                field(balance; Rec."Balance (LCY)") { }
+                field(iban; Rec.IBAN) { }
+                field(paymentTerms; Rec."Payment Terms Code") { }
+            }
+        }
+    }
+}