(new): rich message support

(fix): runtime reliability
(tests): regression coverage
(doc): v1.1 release notes

scene.go

@@ -1,6 +1,7 @@
 package laniakea
 
 import (
+	"bytes"
 	"encoding/json"
 	"maps"
 	"sync"
@@ -131,18 +132,17 @@ type SceneSession struct {
 	Scene string
 	// Step is the current step name inside the active scene.
 	Step string
-	// data stores opaque session payload bytes, typically JSON.
 	data []byte
 }
 
 // SetData stores arbitrary opaque session data.
 func (s *SceneSession) SetData(data []byte) {
-	s.data = data
+	s.data = bytes.Clone(data)
 }
 
 // GetData returns the raw session data payload.
 func (s *SceneSession) GetData() []byte {
-	return s.data
+	return bytes.Clone(s.data)
 }
 
 // HasData reports whether the session has a non-empty data payload.
@@ -198,6 +198,7 @@ func (s *MemorySessionStore) Get(key string) (SceneSession, error) {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 	if session, ok := s.store[key]; ok {
+		session.data = bytes.Clone(session.data)
 		return session, nil
 	}
 	return SceneSession{}, nil
@@ -205,6 +206,7 @@ func (s *MemorySessionStore) Get(key string) (SceneSession, error) {
 
 // Set stores session under key.
 func (s *MemorySessionStore) Set(key string, session SceneSession) error {
+	session.data = bytes.Clone(session.data)
 	s.mu.Lock()
 	s.store[key] = session
 	s.mu.Unlock()