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>

stream_onclose_test.go

@@ -11,7 +11,7 @@ import (
 //
 //	business OnClose -> wait ready -> invoke wait business return -> never Inject.
 func TestStreamOnCloseBeforeInjectDoesNotBlock(t *testing.T) {
-	st := &Stream{}
+	st := &Stream[any]{}
 	registered := make(chan struct{})
 	var called atomic.Int32
 	go func() {
@@ -35,7 +35,7 @@ func TestStreamOnCloseBeforeInjectDoesNotBlock(t *testing.T) {
 }
 
 func TestStreamOnCloseAfterAlreadyClosedRunsImmediately(t *testing.T) {
-	st := &Stream{}
+	st := &Stream[any]{}
 	st.Inject(make(chan any), make(chan struct{}))
 	st.Close()
 	var called atomic.Int32