🐛 fix(duckdb): 修复唯一索引识别与多库对象解析

- 合并 DuckDB 约束与索引元数据，恢复唯一索引表的可编辑判定
- 修复 attach 多库场景下 catalog/schema/table 定位混乱问题
- 统一前后端 qualified name 解析，支持带点和带引号对象名
- 补充 DuckDB 元数据与编辑链路回归测试

internal/app/db_context.go

@@ -58,6 +58,10 @@ func normalizeSchemaAndTable(config connection.ConnectionConfig, dbName string,
 		return targetDB, rawTable
 	}
 
+	if dbType == "duckdb" {
+		return rawDB, rawTable
+	}
+
 	if dbType == "kingbase" {
 		schema, table := db.SplitKingbaseQualifiedName(rawTable)
 		if schema != "" && table != "" {

internal/app/db_context_test.go

@@ -140,6 +140,21 @@ func TestNormalizeSchemaAndTable_OceanBaseOracleUsesSchemaFromDatabaseTree(t *te
 	}
 }
 
+func TestNormalizeSchemaAndTable_DuckDBPreservesQuotedQualifiedName(t *testing.T) {
+	t.Parallel()
+
+	schemaOrDb, table := normalizeSchemaAndTable(connection.ConnectionConfig{
+		Type: "duckdb",
+	}, `"analytics.catalog"."main.schema"`, `"daily.events"."2026.06"`)
+
+	if schemaOrDb != `"analytics.catalog"."main.schema"` {
+		t.Fatalf("expected duckdb dbName/catalog path preserved, got %q", schemaOrDb)
+	}
+	if table != `"daily.events"."2026.06"` {
+		t.Fatalf("expected duckdb qualified table preserved, got %q", table)
+	}
+}
+
 func TestQuoteTableIdentByType_KingbaseNormalizesQuotedQualifiedTable(t *testing.T) {
 	t.Parallel()
 

internal/app/methods_db.go

@@ -320,6 +320,10 @@ func normalizeSchemaAndTableByType(dbType string, dbName string, tableName strin
 		}
 	}
 
+	if dbType == "duckdb" {
+		return rawDB, rawTable
+	}
+
 	if parts := strings.SplitN(rawTable, ".", 2); len(parts) == 2 {
 		schema := strings.TrimSpace(parts[0])
 		table := strings.TrimSpace(parts[1])