fix: close stream adaptive gaps and switch notify to stario v0.1.1

- make stream fast path honor adaptive soft payload limits end-to-end
  - split oversized fast-stream payloads into sequential frames before batching
  - use adaptive soft cap when encoding stream batch payloads
  - move timeout-like error detection into production code for adaptive tx
  - tune notify FrameReader read size explicitly to avoid throughput regression
  - drop local stario replace and depend on released b612.me/stario v0.1.1

timeout_error.go

@@ -0,0 +1,22 @@
+package notify
+
+import (
+	"errors"
+	"net"
+	"os"
+	"strings"
+)
+
+func isTimeoutLikeError(err error) bool {
+	if err == nil {
+		return false
+	}
+	if errors.Is(err, os.ErrDeadlineExceeded) {
+		return true
+	}
+	var netErr net.Error
+	if errors.As(err, &netErr) && netErr.Timeout() {
+		return true
+	}
+	return strings.Contains(strings.ToLower(err.Error()), "timeout")
+}