feat(runtime): IM 主人私聊补历史转录（与 Web 主会话同源：抽共享 transcript 包 + OwnerEnvFor 单入口）

internal/services/gateway/chat_documents_bounds_test.go

@@ -21,6 +21,7 @@ import (
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/history"
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/loop"
 	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/model"
+	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/transcript"
 )
 
 // TestChatDocumentsStreamPathCarriesDocuments 钉住 `stream:true` 这条转发路径：
@@ -92,7 +93,7 @@ func TestTranscriptMessageKeepsDocumentReference(t *testing.T) {
 	if err != nil {
 		t.Fatalf("encode document: %v", err)
 	}
-	msg := transcriptMessage(history.Message{ID: "m1", Role: history.RoleUser, Content: "读一下", Document: raw})
+	msg := transcript.Message(history.Message{ID: "m1", Role: history.RoleUser, Content: "读一下", Document: raw})
 	docs := chatDocumentsOf([]model.Message{msg})
 	if len(docs) != 1 {
 		t.Fatalf("文档引用没能重建回来：%+v", msg)
@@ -103,17 +104,17 @@ func TestTranscriptMessageKeepsDocumentReference(t *testing.T) {
 	}
 	// 没有附件的消息照旧没有文档部件；坏列不 panic 也不产生部件（打 WARN）。
 	if got := chatDocumentsOf([]model.Message{
-		transcriptMessage(history.Message{ID: "m2", Role: history.RoleUser, Content: "无附件"}),
+		transcript.Message(history.Message{ID: "m2", Role: history.RoleUser, Content: "无附件"}),
 	}); len(got) != 0 {
 		t.Fatalf("无附件消息产生了文档部件：%+v", got)
 	}
 	if got := chatDocumentsOf([]model.Message{
-		transcriptMessage(history.Message{ID: "m3", Role: history.RoleUser, Content: "坏列", Document: "{not json"}),
+		transcript.Message(history.Message{ID: "m3", Role: history.RoleUser, Content: "坏列", Document: "{not json"}),
 	}); len(got) != 0 {
 		t.Fatalf("坏列产生了文档部件：%+v", got)
 	}
 	// 助手回合的说话者标注不受本次改动影响；附件不会落到非用户回合上。
-	assistant := transcriptMessage(history.Message{
+	assistant := transcript.Message(history.Message{
 		ID: "m4", Role: history.RoleAssistant, Content: "答复", PersonaID: "cyrene", Document: raw,
 	})
 	if assistant.SenderName != "cyrene" {