feat(notify): 重构通信内核并补齐 stream/bulk/record/transfer 能力

- 引入 LogicalConn/TransportConn 分层，ClientConn 保留兼容适配层
  - 新增 Stream、Bulk、RecordStream 三条数据面能力及对应控制路径
  - 完成 transfer/file 传输内核与状态快照、诊断能力
  - 补齐 reconnect、inbound dispatcher、modern psk 等基础模块
  - 增加大规模回归、并发与基准测试覆盖
  - 更新依赖库

file_ack_flow_test.go

@@ -0,0 +1,107 @@
+package notify
+
+import (
+	"context"
+	"errors"
+	"testing"
+)
+
+func TestRetryFileTransferSendHonorsRetryCount(t *testing.T) {
+	var attempts int
+
+	err := retryFileTransferSend(context.Background(), fileTransferConfig{
+		SendRetry: 3,
+	}, func(cfg fileTransferConfig) error {
+		attempts++
+		return errors.New("send failed")
+	})
+	if err == nil {
+		t.Fatal("retryFileTransferSend should return the last error")
+	}
+	if got, want := attempts, 3; got != want {
+		t.Fatalf("attempt count mismatch: got %d want %d", got, want)
+	}
+}
+
+func TestRetryFileTransferSendStopsAfterSuccess(t *testing.T) {
+	var attempts int
+
+	err := retryFileTransferSend(context.Background(), fileTransferConfig{
+		SendRetry: 5,
+	}, func(cfg fileTransferConfig) error {
+		attempts++
+		if attempts == 3 {
+			return nil
+		}
+		return errors.New("send failed")
+	})
+	if err != nil {
+		t.Fatalf("retryFileTransferSend should stop after success: %v", err)
+	}
+	if got, want := attempts, 3; got != want {
+		t.Fatalf("attempt count mismatch: got %d want %d", got, want)
+	}
+}
+
+func TestRetryFileTransferSendHonorsContextCancel(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	var attempts int
+	err := retryFileTransferSend(ctx, fileTransferConfig{
+		SendRetry: 3,
+	}, func(cfg fileTransferConfig) error {
+		attempts++
+		return nil
+	})
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("expected context canceled, got %v", err)
+	}
+	if got, want := attempts, 0; got != want {
+		t.Fatalf("attempt count mismatch: got %d want %d", got, want)
+	}
+}
+
+func TestRetryFileTransferSendReportsRetryAndTimeoutHooks(t *testing.T) {
+	var attempts int
+	var retries int
+	var timeouts int
+
+	err := retryFileTransferSend(context.Background(), fileTransferConfig{
+		SendRetry: 3,
+	}, func(cfg fileTransferConfig) error {
+		attempts++
+		if attempts < 3 {
+			return errFileAckTimeout
+		}
+		return nil
+	}, fileTransferRetryHooks{
+		onRetry: func(err error, attempt int) {
+			retries++
+			if !errors.Is(err, errFileAckTimeout) {
+				t.Fatalf("retry err = %v, want %v", err, errFileAckTimeout)
+			}
+			if attempt != retries {
+				t.Fatalf("retry attempt = %d, want %d", attempt, retries)
+			}
+		},
+		onTimeout: func(err error, attempt int) {
+			timeouts++
+			if !errors.Is(err, errFileAckTimeout) {
+				t.Fatalf("timeout err = %v, want %v", err, errFileAckTimeout)
+			}
+			if attempt != timeouts {
+				t.Fatalf("timeout attempt = %d, want %d", attempt, timeouts)
+			}
+		},
+	})
+	if err != nil {
+		t.Fatalf("retryFileTransferSend should succeed after timeout retries: %v", err)
+	}
+	if got, want := retries, 2; got != want {
+		t.Fatalf("retry hook count mismatch: got %d want %d", got, want)
+	}
+	if got, want := timeouts, 2; got != want {
+		t.Fatalf("timeout hook count mismatch: got %d want %d", got, want)
+	}
+}