Add TableRelation field-length and RecordRef.Open Temp knowledge

- data-modeling: tablerelation-field-length-must-match-related-field
  (exact length for unconditional relations, at least the longest target
  when all relations are conditional; no compile-time diagnostic)
- testing: recordref-open-temp-parameter-defeats-real-table-checks
  (a temp-opened RecordRef is empty, so existence/uniqueness checks on it
  never see persisted rows; cross-links use-generateguid article)
- Wire both into the review leaves and register the fixture pairs.

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

microsoft/knowledge/data-modeling/tablerelation-field-length-must-match-related-field.good.al

@@ -0,0 +1,58 @@
+enum 50100 "Sample Source Type"
+{
+    Extensible = true;
+
+    value(0; Category) { }
+    value(1; Region) { }
+}
+
+table 50100 "Sample Category"
+{
+    fields
+    {
+        field(1; "Code"; Code[20]) { }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}
+
+table 50101 "Sample Region"
+{
+    fields
+    {
+        field(1; "Code"; Code[10]) { }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}
+
+table 50102 "Sample Contract"
+{
+    fields
+    {
+        field(1; "Code"; Code[20]) { }
+        // Unconditional relation: same type and exactly the same length as
+        // "Sample Category"."Code".
+        field(2; "Category Code"; Code[20])
+        {
+            TableRelation = "Sample Category"."Code";
+        }
+        field(3; "Source Type"; Enum "Sample Source Type") { }
+        // All branches conditional: at least as long as the longest related
+        // field (Code[20] covers both Code[20] and Code[10]).
+        field(4; "Source Code"; Code[20])
+        {
+            TableRelation = if ("Source Type" = const(Category)) "Sample Category"."Code"
+            else
+            if ("Source Type" = const(Region)) "Sample Region"."Code";
+        }
+    }
+    keys
+    {
+        key(PK; "Code") { Clustered = true; }
+    }
+}