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

session_state_test.go

@@ -0,0 +1,77 @@
+package notify
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"sync/atomic"
+	"testing"
+)
+
+func TestSessionIsAliveHandlesUninitializedValue(t *testing.T) {
+	var alive atomic.Value
+	if sessionIsAlive(&alive) {
+		t.Fatal("uninitialized alive should be false")
+	}
+}
+
+func TestSessionMarkStartedUpdatesAliveAndStatus(t *testing.T) {
+	var alive atomic.Value
+	alive.Store(false)
+	status := Status{Alive: false, Reason: "old", Err: errors.New("old")}
+	var mu sync.Mutex
+
+	sessionMarkStarted(&alive, &mu, &status)
+
+	gotAlive, _ := alive.Load().(bool)
+	if !gotAlive {
+		t.Fatal("alive not marked true")
+	}
+	if !status.Alive || status.Reason != "" || status.Err != nil {
+		t.Fatalf("unexpected status after start: %+v", status)
+	}
+}
+
+func TestSessionMarkStoppedRunsCleanupAndStop(t *testing.T) {
+	var alive atomic.Value
+	alive.Store(true)
+	status := Status{Alive: true}
+	stopCtx, stopFn := context.WithCancel(context.Background())
+	defer stopFn()
+
+	cleanupCalls := 0
+	boom := errors.New("boom")
+
+	sessionMarkStopped(&alive, nil, &status, "stopped", boom, stopFn,
+		func() { cleanupCalls++ },
+		func() { cleanupCalls++ },
+	)
+
+	gotAlive, _ := alive.Load().(bool)
+	if gotAlive {
+		t.Fatal("alive not marked false")
+	}
+	if status.Alive || status.Reason != "stopped" || !errors.Is(status.Err, boom) {
+		t.Fatalf("unexpected status after stop: %+v", status)
+	}
+	if cleanupCalls != 2 {
+		t.Fatalf("cleanupCalls = %d, want 2", cleanupCalls)
+	}
+	select {
+	case <-stopCtx.Done():
+	default:
+		t.Fatal("stop function was not called")
+	}
+}
+
+func TestSessionStatusValueReturnsCopy(t *testing.T) {
+	status := Status{Alive: true, Reason: "ok"}
+	var mu sync.Mutex
+
+	snapshot := sessionStatusValue(&mu, &status)
+	status.Reason = "changed"
+
+	if snapshot.Reason != "ok" {
+		t.Fatalf("snapshot.Reason = %q, want ok", snapshot.Reason)
+	}
+}