🐛 fix(mysql): 兼容 MyCAT 场景下数据库列表解析逻辑

- 扩展数据库名字段识别，兼容 SCHEMA、database_name 等返回列名
- 按驱动返回列顺序兜底提取单列结果，避免非标准列名导致误判为空
- 补充 MyCAT 风格回归测试，覆盖 SHOW DATABASES 与当前库回退逻辑
Close #552

internal/ai/service/mcp_http_server.go

@@ -163,7 +163,8 @@ func (s *Service) stopMCPHTTPServer(ctx context.Context, message string) (ai.MCP
 }
 
 // Shutdown 释放 AI Service 中的运行时资源。
-func (s *Service) Shutdown(ctx context.Context) {
+func (s *Service) Shutdown() {
+	ctx := context.Background()
 	_, _ = s.stopMCPHTTPServer(ctx, "应用关闭，GoNavi MCP HTTP 服务已停止")
 }
 

internal/ai/service/mcp_http_server_test.go

@@ -57,7 +57,7 @@ func TestMCPHTTPServerLifecycleFromAIService(t *testing.T) {
 	service := NewServiceWithSecretStore(secretstore.NewUnavailableStore("test"))
 	InitializeLifecycle(service, context.Background())
 	t.Cleanup(func() {
-		service.Shutdown(context.Background())
+		service.Shutdown()
 	})
 
 	initial := service.AIGetMCPHTTPServerStatus()
@@ -123,7 +123,7 @@ func TestMCPHTTPServerStartUsesCustomAddrAndToken(t *testing.T) {
 	service := NewServiceWithSecretStore(secretstore.NewUnavailableStore("test"))
 	InitializeLifecycle(service, context.Background())
 	t.Cleanup(func() {
-		service.Shutdown(context.Background())
+		service.Shutdown()
 	})
 
 	started, err := service.AIStartMCPHTTPServer(ai.MCPHTTPServerOptions{

internal/app/app.go

@@ -178,8 +178,8 @@ func (a *App) LogWindowDiagnostic(stage string, payload string) {
 	logger.Warnf("窗口诊断：stage=%s payload=%s", stage, payload)
 }
 
-// Shutdown is called when the app terminates
-func (a *App) Shutdown(ctx context.Context) {
+// Shutdown is called when the app terminates.
+func (a *App) Shutdown() {
 	logger.Infof("应用开始关闭，准备释放资源")
 	a.rollbackPendingSQLTransactionsOnShutdown()
 	a.mu.Lock()

internal/db/mysql_impl.go

@@ -594,6 +594,18 @@ var mysqlDatabaseQueries = []string{
 	"SELECT DATABASE() AS `Database`",
 }
 
+var mysqlDatabaseNameKeys = []string{
+	"Database",
+	"database",
+	"DATABASE",
+	"database_name",
+	"DATABASE_NAME",
+	"schema",
+	"SCHEMA",
+	"schema_name",
+	"SCHEMA_NAME",
+}
+
 func collectMySQLDatabaseNames(queryFn func(string) ([]map[string]interface{}, []string, error)) ([]string, error) {
 	if queryFn == nil {
 		return nil, fmt.Errorf("查询函数为空")
@@ -603,34 +615,59 @@ func collectMySQLDatabaseNames(queryFn func(string) ([]map[string]interface{}, [
 	seen := make(map[string]struct{}, 8)
 	var lastErr error
 
-	appendNames := func(rows []map[string]interface{}) {
-		for _, row := range rows {
-			for _, key := range []string{"Database", "database"} {
-				val, ok := row[key]
-				if !ok || val == nil {
-					continue
-				}
-				name := strings.TrimSpace(fmt.Sprintf("%v", val))
-				if name == "" || strings.EqualFold(name, "<nil>") {
-					continue
-				}
-				if _, exists := seen[name]; exists {
-					continue
-				}
-				seen[name] = struct{}{}
-				names = append(names, name)
-				break
+	normalizeName := func(val interface{}) string {
+		if val == nil {
+			return ""
+		}
+		name := strings.TrimSpace(fmt.Sprintf("%v", val))
+		if name == "" || strings.EqualFold(name, "<nil>") || strings.EqualFold(name, "null") {
+			return ""
+		}
+		return name
+	}
+
+	extractName := func(row map[string]interface{}, columns []string) string {
+		for _, key := range mysqlDatabaseNameKeys {
+			if name := normalizeName(row[key]); name != "" {
+				return name
 			}
 		}
+		for _, column := range columns {
+			if name := normalizeName(row[column]); name != "" {
+				return name
+			}
+		}
+		if len(row) == 1 {
+			for _, val := range row {
+				if name := normalizeName(val); name != "" {
+					return name
+				}
+			}
+		}
+		return ""
+	}
+
+	appendNames := func(rows []map[string]interface{}, columns []string) {
+		for _, row := range rows {
+			name := extractName(row, columns)
+			if name == "" {
+				continue
+			}
+			if _, exists := seen[name]; exists {
+				continue
+			}
+			seen[name] = struct{}{}
+			names = append(names, name)
+		}
 	}
 
 	for _, sqlText := range mysqlDatabaseQueries {
-		rows, _, err := queryFn(sqlText)
+		rows, columns, err := queryFn(sqlText)
 		if err != nil {
 			lastErr = err
 			continue
 		}
-		appendNames(rows)
+		appendNames(rows, columns)
 		if len(names) > 0 {
 			return names, nil
 		}

internal/db/mysql_metadata_test.go

@@ -15,8 +15,8 @@ func TestCollectMySQLDatabaseNames_FallsBackToCurrentDatabase(t *testing.T) {
 			return nil, nil, errors.New("Error 1227 (42000): Access denied; you need (at least one of) the SHOW DATABASES privilege(s) for this operation")
 		case mysqlDatabaseQueries[1]:
 			return []map[string]interface{}{
-				{"Database": "biz_app"},
-			}, nil, nil
+				{"database_name": "biz_app"},
+			}, []string{"database_name"}, nil
 		default:
 			return nil, nil, errors.New("unexpected query")
 		}
@@ -31,6 +31,33 @@ func TestCollectMySQLDatabaseNames_FallsBackToCurrentDatabase(t *testing.T) {
 	}
 }
 
+func TestCollectMySQLDatabaseNames_AcceptsMyCATStyleSchemaColumn(t *testing.T) {
+	t.Parallel()
+
+	got, err := collectMySQLDatabaseNames(func(query string) ([]map[string]interface{}, []string, error) {
+		switch query {
+		case mysqlDatabaseQueries[0]:
+			return []map[string]interface{}{
+				{"SCHEMA": "analytics"},
+			}, []string{"SCHEMA"}, nil
+		case mysqlDatabaseQueries[1]:
+			return []map[string]interface{}{
+				{"Database": "should_not_be_used"},
+			}, []string{"Database"}, nil
+		default:
+			return nil, nil, errors.New("unexpected query")
+		}
+	})
+	if err != nil {
+		t.Fatalf("collectMySQLDatabaseNames 返回错误: %v", err)
+	}
+
+	want := []string{"analytics"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("unexpected database names, got=%v want=%v", got, want)
+	}
+}
+
 func TestCollectMySQLDatabaseNames_PrefersShowDatabasesWhenAvailable(t *testing.T) {
 	t.Parallel()
 

internal/mcpserver/backend.go

@@ -47,10 +47,7 @@ func (b *AppBackend) Close(ctx context.Context) error {
 	if b == nil || b.app == nil {
 		return nil
 	}
-	if ctx == nil {
-		ctx = context.Background()
-	}
-	b.app.Shutdown(ctx)
+	b.app.Shutdown()
 	return nil
 }