🐛 fix(query-export): 修复查询结果导出卡住并统一按数据源能力控制导出路径

- 查询结果页导出增加稳定兜底，异常时确保 loading 关闭避免持续转圈
- DataGrid 导出逻辑按数据源能力分流，优先走后端 ExportQuery 并保留结果集导出降级
- QueryEditor 传递结果导出 SQL，保证查询结果导出范围与当前结果一致
- 后端补充 ExportData/ExportQuery 关键日志，提升导出链路可观测性

cmd/optional-driver-agent/main_test.go

@@ -3,8 +3,13 @@ package main
 import (
 	"bufio"
 	"bytes"
+	"context"
 	"encoding/json"
+	"errors"
 	"testing"
+	"time"
+
+	"GoNavi-Wails/internal/connection"
 )
 
 type duckMapLike map[any]any
@@ -60,3 +65,108 @@ func TestNormalizeAgentResponseData_KeepByteSlice(t *testing.T) {
 		t.Fatalf("[]byte 内容被意外改写: %v", out)
 	}
 }
+
+type fakeAgentTimeoutDB struct {
+	queryCalled        bool
+	queryContextCalled bool
+	execCalled         bool
+	execContextCalled  bool
+	deadlineSet        bool
+}
+
+func (f *fakeAgentTimeoutDB) Connect(config connection.ConnectionConfig) error { return nil }
+func (f *fakeAgentTimeoutDB) Close() error                                     { return nil }
+func (f *fakeAgentTimeoutDB) Ping() error                                      { return nil }
+func (f *fakeAgentTimeoutDB) Query(query string) ([]map[string]interface{}, []string, error) {
+	f.queryCalled = true
+	return nil, nil, errors.New("query should not be called")
+}
+func (f *fakeAgentTimeoutDB) QueryContext(ctx context.Context, query string) ([]map[string]interface{}, []string, error) {
+	f.queryContextCalled = true
+	if _, ok := ctx.Deadline(); ok {
+		f.deadlineSet = true
+	}
+	return []map[string]interface{}{{"ok": 1}}, []string{"ok"}, nil
+}
+func (f *fakeAgentTimeoutDB) Exec(query string) (int64, error) {
+	f.execCalled = true
+	return 0, errors.New("exec should not be called")
+}
+func (f *fakeAgentTimeoutDB) ExecContext(ctx context.Context, query string) (int64, error) {
+	f.execContextCalled = true
+	if _, ok := ctx.Deadline(); ok {
+		f.deadlineSet = true
+	}
+	return 3, nil
+}
+func (f *fakeAgentTimeoutDB) GetDatabases() ([]string, error) { return nil, nil }
+func (f *fakeAgentTimeoutDB) GetTables(dbName string) ([]string, error) {
+	return nil, nil
+}
+func (f *fakeAgentTimeoutDB) GetCreateStatement(dbName, tableName string) (string, error) {
+	return "", nil
+}
+func (f *fakeAgentTimeoutDB) GetColumns(dbName, tableName string) ([]connection.ColumnDefinition, error) {
+	return nil, nil
+}
+func (f *fakeAgentTimeoutDB) GetAllColumns(dbName string) ([]connection.ColumnDefinitionWithTable, error) {
+	return nil, nil
+}
+func (f *fakeAgentTimeoutDB) GetIndexes(dbName, tableName string) ([]connection.IndexDefinition, error) {
+	return nil, nil
+}
+func (f *fakeAgentTimeoutDB) GetForeignKeys(dbName, tableName string) ([]connection.ForeignKeyDefinition, error) {
+	return nil, nil
+}
+func (f *fakeAgentTimeoutDB) GetTriggers(dbName, tableName string) ([]connection.TriggerDefinition, error) {
+	return nil, nil
+}
+
+func TestQueryWithOptionalTimeout_UsesQueryContext(t *testing.T) {
+	fake := &fakeAgentTimeoutDB{}
+	data, fields, err := queryWithOptionalTimeout(fake, "SELECT 1", int64((2 * time.Second).Milliseconds()))
+	if err != nil {
+		t.Fatalf("queryWithOptionalTimeout 返回错误: %v", err)
+	}
+	if !fake.queryContextCalled || fake.queryCalled {
+		t.Fatalf("query 调用路径异常，QueryContext=%v Query=%v", fake.queryContextCalled, fake.queryCalled)
+	}
+	if !fake.deadlineSet {
+		t.Fatal("queryWithOptionalTimeout 未设置 deadline")
+	}
+	if len(data) != 1 || len(fields) != 1 || fields[0] != "ok" {
+		t.Fatalf("queryWithOptionalTimeout 返回数据异常: data=%v fields=%v", data, fields)
+	}
+}
+
+func TestExecWithOptionalTimeout_UsesExecContext(t *testing.T) {
+	fake := &fakeAgentTimeoutDB{}
+	affected, err := execWithOptionalTimeout(fake, "DELETE FROM t", int64((2 * time.Second).Milliseconds()))
+	if err != nil {
+		t.Fatalf("execWithOptionalTimeout 返回错误: %v", err)
+	}
+	if !fake.execContextCalled || fake.execCalled {
+		t.Fatalf("exec 调用路径异常，ExecContext=%v Exec=%v", fake.execContextCalled, fake.execCalled)
+	}
+	if !fake.deadlineSet {
+		t.Fatal("execWithOptionalTimeout 未设置 deadline")
+	}
+	if affected != 3 {
+		t.Fatalf("受影响行数异常，want=3 got=%d", affected)
+	}
+}
+
+func TestQueryWithOptionalTimeout_ClickHouseLegacyModeUsesQueryContext(t *testing.T) {
+	old := agentDriverType
+	agentDriverType = "clickhouse"
+	defer func() { agentDriverType = old }()
+
+	fake := &fakeAgentTimeoutDB{}
+	_, _, err := queryWithOptionalTimeout(fake, "SELECT 1", 0)
+	if err != nil {
+		t.Fatalf("queryWithOptionalTimeout 返回错误: %v", err)
+	}
+	if !fake.queryContextCalled || fake.queryCalled {
+		t.Fatalf("clickhouse legacy query 调用路径异常，QueryContext=%v Query=%v", fake.queryContextCalled, fake.queryCalled)
+	}
+}