v1.4.0: generic Stream[T] — typed stream messages, drop (T, *Stream, error)

- Stream[T]: Send(v T) type-safe; message type recovered from the
  instantiated Send signature (reflect has no type-args API)
- method signatures reduced to (error), (T, error), (*Stream[T], error);
  the (T, *Stream, error) first-message form is gone — send it via Send
- return T and stream message T now run checkType at bind time
  (Stream[any] remains the explicit untyped escape hatch)
- generated clients: TS onMessage: (data: T); Go <-chan T
- fix vacuous panic assertions (fmt.Sprint(nil) -> "<nil>") in
  hardening/route test catch helpers

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

fun_test.go

@@ -44,8 +44,8 @@ func (s *TestSvc) Hello(dto TestDto) (string, error) {
 	return "hi " + dto.Name, nil
 }
 
-func (s *TestSvc) Count(dto TestDto) (*Stream, error) {
-	st := Stream{}
+func (s *TestSvc) Count(dto TestDto) (*Stream[string], error) {
+	st := &Stream[string]{}
 	go func() {
 		for i := 0; i < 3; i++ {
 			st.Send(fmt.Sprintf("n%d", i))
@@ -53,7 +53,7 @@ func (s *TestSvc) Count(dto TestDto) (*Stream, error) {
 		}
 		st.Close()
 	}()
-	return &st, nil
+	return st, nil
 }
 
 func TestCtxBoxInject(t *testing.T) {