Fix SQL generated-column reference persistence

DEVELOPER_GUIDE.md

@@ -864,6 +864,7 @@ filters remain exact, so `--kind import` does not include local type declaration
 | `extends` | Inheritance or type-extension relationship |
 | `from` | Dockerfile `FROM <stage>` dependency |
 | `friend` | C++ friend declaration relationship |
+| `generated_column_dependency` | SQL generated/computed-column expression dependency |
 | `generic_type_argument` | Generic type argument attached to an explicit invocation |
 | `implement` | Interface implementation relationship |
 | `implicit_implementation` | C# implicit interface implementation relationship |
@@ -4271,6 +4272,7 @@ filter、downstream JSON consumer が同じ値を理解できるようにして
 | `extends` | inheritance または type-extension relationship |
 | `from` | Dockerfile `FROM <stage>` dependency |
 | `friend` | C++ friend declaration relationship |
+| `generated_column_dependency` | SQL generated / computed column 式の dependency |
 | `generic_type_argument` | explicit invocation に付随する generic type argument |
 | `implement` | interface implementation relationship |
 | `implicit_implementation` | C# implicit interface implementation relationship |

changelog.d/unreleased/+sql-generated-column-reference-kind.fixed.md

@@ -0,0 +1,15 @@
+---
+category: fixed
+affected:
+  - src/CodeIndex/Models/SymbolKindCatalog.cs
+  - tests/CodeIndex.Tests/ReferenceExtractorTests.cs
+  - DEVELOPER_GUIDE.md
+---
+
+## English
+
+- **SQL generated-column references no longer fail during indexing** — registered the `generated_column_dependency` reference kind emitted for generated/computed-column expressions, so persisting SQL reference batches no longer raises `ArgumentException`.
+
+## 日本語
+
+- **SQL generated column の参照で index が失敗しなくなりました** — generated / computed column 式で抽出される `generated_column_dependency` reference kind を登録し、SQL reference batch の永続化時に `ArgumentException` が発生しないようにしました。

src/CodeIndex/Models/SymbolKindCatalog.cs

@@ -113,6 +113,7 @@ public static class SymbolKindCatalog
         "extends",
         "from",
         "friend",
+        "generated_column_dependency",
         "generic_type_argument",
         "implement",
         "implicit_implementation",

tests/CodeIndex.Tests/ReferenceExtractorTests.cs

@@ -8739,6 +8739,11 @@ created_at timestamp DEFAULT CURRENT_TIMESTAMP
         Assert.DoesNotContain(references, r => r.SymbolName == "GENERATED" && r.ReferenceKind == "generated_column_dependency");
         Assert.DoesNotContain(references, r => r.SymbolName == "DEFAULT" && r.ReferenceKind == "generated_column_dependency");
         Assert.DoesNotContain(references, r => r.SymbolName == "CURRENT_TIMESTAMP" && r.ReferenceKind == "generated_column_dependency");
+        Assert.All(
+            references,
+            reference => Assert.True(
+                SymbolKindCatalog.IsValidReferenceKind(reference.ReferenceKind),
+                $"SQL extractor emitted unregistered reference kind '{reference.ReferenceKind}'."));
     }
 
     [Fact]