Add trigger-default and declined-Confirm knowledge with review cues

Three Microsoft-layer articles with good/bad samples:
- error-handling/declined-confirm-must-abort-not-partially-apply
- data-modeling/delete-master-data-with-trigger
- data-modeling/master-data-must-be-inserted-with-trigger

Wire targeted worklist cues into al-error-handling-review and
al-data-modeling-review and register the samples in review-fixtures.json.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

microsoft/knowledge/error-handling/declined-confirm-must-abort-not-partially-apply.bad.al

@@ -0,0 +1,46 @@
+table 50100 "Sample Mailbox Watch"
+{
+    fields
+    {
+        field(1; "Code"; Code[20])
+        {
+        }
+        field(2; "Watched Email"; Text[250])
+        {
+            trigger OnValidate()
+            var
+                StopWatchingQst: Label 'Email %1 is being watched. Stop watching it?', Comment = '%1 = previous email address';
+            begin
+                if (xRec."Watched Email" <> '') and (xRec."Watched Email" <> "Watched Email") then
+                    if Confirm(StopWatchingQst, false, xRec."Watched Email") then
+                        Unsubscribe("Subscription ID");
+                // On "no" the old subscription is never removed, and the only field
+                // that tracked it is overwritten here: it is orphaned.
+                "Subscription ID" := Subscribe("Watched Email");
+            end;
+        }
+        field(3; "Subscription ID"; Guid)
+        {
+            Editable = false;
+        }
+    }
+
+    keys
+    {
+        key(PK; "Code")
+        {
+            Clustered = true;
+        }
+    }
+
+    local procedure Subscribe(EmailAddress: Text[250]): Guid
+    begin
+        // Registers EmailAddress with the external watch service and returns its subscription.
+        exit(CreateGuid());
+    end;
+
+    local procedure Unsubscribe(SubscriptionId: Guid)
+    begin
+        // Removes the subscription from the external watch service.
+    end;
+}

microsoft/knowledge/error-handling/declined-confirm-must-abort-not-partially-apply.good.al

@@ -0,0 +1,47 @@
+table 50100 "Sample Mailbox Watch"
+{
+    fields
+    {
+        field(1; "Code"; Code[20])
+        {
+        }
+        field(2; "Watched Email"; Text[250])
+        {
+            trigger OnValidate()
+            var
+                ReplaceWatchQst: Label 'Email %1 is being watched. Stop watching it and watch %2 instead?', Comment = '%1 = previous email address, %2 = new email address';
+            begin
+                if (xRec."Watched Email" <> '') and (xRec."Watched Email" <> "Watched Email") then begin
+                    // Declining cancels the whole change: the field keeps its old value.
+                    if not Confirm(ReplaceWatchQst, false, xRec."Watched Email", "Watched Email") then
+                        Error('');
+                    Unsubscribe("Subscription ID");
+                end;
+                "Subscription ID" := Subscribe("Watched Email");
+            end;
+        }
+        field(3; "Subscription ID"; Guid)
+        {
+            Editable = false;
+        }
+    }
+
+    keys
+    {
+        key(PK; "Code")
+        {
+            Clustered = true;
+        }
+    }
+
+    local procedure Subscribe(EmailAddress: Text[250]): Guid
+    begin
+        // Registers EmailAddress with the external watch service and returns its subscription.
+        exit(CreateGuid());
+    end;
+
+    local procedure Unsubscribe(SubscriptionId: Guid)
+    begin
+        // Removes the subscription from the external watch service.
+    end;
+}

microsoft/knowledge/error-handling/declined-confirm-must-abort-not-partially-apply.md

@@ -0,0 +1,41 @@
+---
+bc-version: [all]
+domain: error-handling
+keywords: [confirm, onvalidate, xrec, abort, revert, side-effect, consistency]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+
+# A declined `Confirm` in `OnValidate` must abort or revert, not skip a required side effect
+
+## Description
+
+By the time a field's `OnValidate` body runs, the field already holds its new value. When the trigger asks the user to confirm a side effect that the new value makes **required for consistency** — releasing or replacing state that is tied to the old value and that nothing will reference after the change — the shape `if Confirm(...) then <side effect>;` with nothing on the `false` branch lets the new value commit while silently skipping that effect. No error is raised, the user sees no indication that anything was declined, and the record is left inconsistent with its own dependents.
+
+Not every confirmed follow-up is required. When the confirmed effect is a convenience the user may legitimately decline, skipping it is correct: `"Sales Header"`'s `UpdateSalesLinesByFieldNo` asks whether to update the lines after a header field changes and, on "no", simply `exit`s — the header keeps its new value and the lines stay as they were, by design. A `Confirm` at the top of an action procedure, before anything has been written, may also just `exit` on "no" (for example the delete action in `"Test Input Groups"`). Neither shape is this anti-pattern.
+
+## Best Practice
+
+Make the declined branch match what "no" means:
+
+- **Cancel the whole change** — raise an error before the side effect. The usual BCApps form inside `OnValidate` is the silent abort `if not Confirm(...) then Error('');` (for example `"Bank Account"`, field `"Disable Bank Rec. Optimization"`). The field trigger documentation states that in case of an error "the user entry is not written to the database."
+- **Keep the old value but let the rest of the edit continue** — assign the field back in code. `"Upload And Deploy Extension"` resets its sync-mode value to `Add` when the user declines `Force Sync`.
+
+Ask before the side effect runs, and before taking locks the prompt would hold open (see [`avoid-user-prompts-inside-transactions`](../performance/avoid-user-prompts-inside-transactions.md)).
+
+See sample: [`declined-confirm-must-abort-not-partially-apply.good.al`](declined-confirm-must-abort-not-partially-apply.good.al).
+
+## Anti Pattern
+
+Inside a field `OnValidate` (or a procedure it calls), a `Confirm` gates a side effect that releases, cancels, or replaces state belonging to the old value (`xRec`), the `false` branch neither errors nor restores the field, and code after it proceeds as if the change were accepted — for example overwriting the only field that tracks the old state. Declining leaves that state orphaned. Do not flag optional follow-ups whose skipping leaves every record consistent, or `exit` on "no" in an action before any write.
+
+See sample: [`declined-confirm-must-abort-not-partially-apply.bad.al`](declined-confirm-must-abort-not-partially-apply.bad.al).
+
+## References
+
+- [OnValidate (Field) trigger](https://learn.microsoft.com/dynamics365/business-central/dev-itpro/developer/triggers-auto/field/devenv-onvalidate-field-trigger).
+- BCApps `src/Layers/W1/BaseApp/Bank/BankAccount/BankAccount.Table.al`, lines 980-988 (silent abort in `OnValidate`).
+- BCApps `src/System Application/App/Extension Management/src/UploadAndDeployExtension.Page.al`, lines 78-83 (explicit revert).
+- BCApps `src/Layers/W1/BaseApp/Sales/Document/SalesHeader.Table.al`, `UpdateSalesLinesByFieldNo`, lines 4997-5014 (optional follow-up; `end else exit`).
+- BCApps `src/Tools/Test Framework/Test Runner/src/DataDrivenTest/DataInputs/TestInputGroups.Page.al`, lines 85-86 (`exit` before any write).