✨ feat(data-import): 重构大文件导入与安全任务运行时

- SQL、CSV、JSON 与 XLSX 改为资源受限的流式解析，并支持压缩、编码和方言预检

- 增加遇错停止/继续策略、持久任务、错误行导出、源文件身份与安全取消

- 为数据库驱动补齐上下文事务和写入结果未知语义，避免失败重放与脏会话复用

internal/app/sql_split_stream_test.go

@@ -39,3 +39,68 @@ func TestSQLStreamSplitterPreservesExecutableMySQLComment(t *testing.T) {
 		t.Fatalf("expected statements %#v, got %#v", want, got)
 	}
 }
+
+func TestSQLStreamSplitterTransactionBeginFormsAcrossChunkBoundaries(t *testing.T) {
+	tests := []struct {
+		dbType string
+		begin  string
+	}{
+		{dbType: "sqlserver", begin: "BEGIN TRAN"},
+		{dbType: "sqlserver", begin: "BEGIN DISTRIBUTED TRANSACTION"},
+		{dbType: "sqlserver", begin: "BEGIN DIALOG CONVERSATION @handle"},
+		{dbType: "sqlserver", begin: "BEGIN CONVERSATION TIMER (@handle) TIMEOUT = 30"},
+		{dbType: "sqlite", begin: "BEGIN IMMEDIATE"},
+		{dbType: "postgres", begin: "BEGIN NOT DEFERRABLE"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.dbType+" "+test.begin, func(t *testing.T) {
+			input := test.begin + "; UPDATE demo SET value = 2; COMMIT;"
+			splitter := &sqlStreamSplitter{dbType: test.dbType}
+			var got []string
+			for index := range len(input) {
+				got = append(got, splitter.Feed([]byte(input[index:index+1]))...)
+			}
+			if last := splitter.Flush(); last != "" {
+				got = append(got, last)
+			}
+			want := []string{test.begin, "UPDATE demo SET value = 2", "COMMIT"}
+			if !reflect.DeepEqual(got, want) {
+				t.Fatalf("one-byte streaming split of %q = %#v, want %#v", input, got, want)
+			}
+		})
+	}
+}
+
+func TestSQLStreamSplitterKeepsMariaDBNotAtomicBlockAcrossChunkBoundaries(t *testing.T) {
+	block := "BEGIN NOT ATOMIC\n  SET @value = 1;\nEND"
+	input := block + "; SELECT 1;"
+	splitter := &sqlStreamSplitter{dbType: "mariadb"}
+	var got []string
+	for index := range len(input) {
+		got = append(got, splitter.Feed([]byte(input[index:index+1]))...)
+	}
+	if last := splitter.Flush(); last != "" {
+		got = append(got, last)
+	}
+	want := []string{block + ";", "SELECT 1"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("one-byte streaming split of %q = %#v, want %#v", input, got, want)
+	}
+}
+
+func TestSQLStreamSplitterUsesDialectForAmbiguousBeginTran(t *testing.T) {
+	input := "BEGIN\n  TRAN;\nEND;\nSELECT 1 FROM dual;"
+	splitter := &sqlStreamSplitter{dbType: "oracle"}
+	var got []string
+	for index := range len(input) {
+		got = append(got, splitter.Feed([]byte(input[index:index+1]))...)
+	}
+	if last := splitter.Flush(); last != "" {
+		got = append(got, last)
+	}
+	want := []string{"BEGIN\n  TRAN;\nEND;", "SELECT 1 FROM dual"}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("one-byte Oracle BEGIN TRAN procedure block = %#v, want %#v", got, want)
+	}
+}