fix(bun): use PostgreSQL internal array type name for sqltypes array columns

bun's pgdialect overrides Field.Scan/Append with its own slice-only array
handling whenever the tag's type: value ends in "[]", clobbering the
sql.Scanner/driver.Valuer implemented on SqlXxxArray wrapper types and
causing "bun: Scan(unsupported sqltypes.SqlStringArray)" at query time.
Emit the underscore-prefixed internal type name (e.g. _text) instead,
which is DDL-valid but doesn't end in "[]" so bun leaves our scanner alone.

pkg/writers/bun/writer_test.go

@@ -827,9 +827,45 @@ func TestTypeMapper_BuildBunTag(t *testing.T) {
 					t.Errorf("BuildBunTag() = %q, missing %q", result, part)
 				}
 			}
-			// sqltypes mode must NOT add "array" — SqlXxxArray uses sql.Scanner
+			// baselib mode must NOT add "array" — the Go type is already a
+			// real slice ([]string, []int32, ...), which bun's pgdialect
+			// scans natively without the explicit "array" tag option.
 			if strings.Contains(result, ",array,") || strings.HasSuffix(result, ",array,") {
-				t.Errorf("BuildBunTag() = %q, must not contain 'array' in sqltypes mode", result)
+				t.Errorf("BuildBunTag() = %q, must not contain 'array' in baselib mode", result)
+			}
+		})
+	}
+}
+
+// TestTypeMapper_BuildBunTag_SqlTypesArrayUsesInternalTypeName verifies that
+// array columns in sqltypes mode never produce a "[]"-suffixed "type:" tag.
+// bun's pgdialect unconditionally overrides Field.Scan/Append with its own
+// (slice-only) array handling whenever the tag's "type:" value ends in "[]",
+// which clobbers the sql.Scanner/driver.Valuer implemented on the
+// SqlXxxArray wrapper types and produces
+// "bun: Scan(unsupported sqltypes.SqlXxxArray)" at query time.
+func TestTypeMapper_BuildBunTag_SqlTypesArrayUsesInternalTypeName(t *testing.T) {
+	mapper := NewTypeMapper(writers.NullableTypeSqlTypes)
+
+	cases := []struct {
+		name       string
+		column     *models.Column
+		wantSubstr string
+	}{
+		{name: "text array", column: &models.Column{Name: "tags", Type: "text[]"}, wantSubstr: "type:_text,"},
+		{name: "varchar array", column: &models.Column{Name: "labels", Type: "varchar[]"}, wantSubstr: "type:_varchar,"},
+		{name: "integer array", column: &models.Column{Name: "scores", Type: "integer[]", NotNull: true}, wantSubstr: "type:_int4,"},
+		{name: "boolean array", column: &models.Column{Name: "flags", Type: "boolean[]"}, wantSubstr: "type:_bool,"},
+		{name: "uuid array", column: &models.Column{Name: "ids", Type: "uuid[]"}, wantSubstr: "type:_uuid,"},
+	}
+	for _, tt := range cases {
+		t.Run(tt.name, func(t *testing.T) {
+			result := mapper.BuildBunTag(tt.column, nil)
+			if !strings.Contains(result, tt.wantSubstr) {
+				t.Errorf("BuildBunTag() = %q, missing %q", result, tt.wantSubstr)
+			}
+			if strings.Contains(result, "[]") {
+				t.Errorf("BuildBunTag() = %q, must not use a \"[]\"-suffixed type in sqltypes mode", result)
 			}
 		})
 	}