fix: 自动标题取消语义、清洗循环与拒绝占位回写

spawn_task 标题 20s 超时且父 ctx 取消不建任务；清洗循环剥前缀内外引号；
异步标题拒绝「新对话」并用条件更新防手改竞态；会话 profile 失败回退全局。

agent/auto_title.go

@@ -51,22 +51,23 @@ func cleanAutoTitle(raw string) string {
 	if i := strings.IndexAny(title, "\r\n"); i >= 0 {
 		title = strings.TrimSpace(title[:i])
 	}
-	for len(title) >= 2 {
-		first, firstSize := utf8.DecodeRuneInString(title)
-		last, lastSize := utf8.DecodeLastRuneInString(title)
-		if (first == '"' && last == '"') || (first == '\'' && last == '\'') || (first == '“' && last == '”') || (first == '「' && last == '」') {
-			title = strings.TrimSpace(title[firstSize : len(title)-lastSize])
-			continue
+	for {
+		previous := title
+		if len(title) >= 2 {
+			first, firstSize := utf8.DecodeRuneInString(title)
+			last, lastSize := utf8.DecodeLastRuneInString(title)
+			if (first == '"' && last == '"') || (first == '\'' && last == '\'') || (first == '“' && last == '”') || (first == '「' && last == '」') {
+				title = title[firstSize : len(title)-lastSize]
+			}
 		}
-		break
-	}
-	lines := strings.FieldsFunc(title, func(r rune) bool { return r == '\r' || r == '\n' })
-	if len(lines) > 0 {
-		title = strings.TrimSpace(lines[0])
-	}
-	for _, prefix := range []string{"标题：", "标题:"} {
-		if strings.HasPrefix(title, prefix) {
-			title = strings.TrimSpace(strings.TrimPrefix(title, prefix))
+		for _, prefix := range []string{"标题：", "标题:"} {
+			if strings.HasPrefix(title, prefix) {
+				title = strings.TrimPrefix(title, prefix)
+				break
+			}
+		}
+		title = strings.TrimSpace(title)
+		if title == previous {
 			break
 		}
 	}

agent/auto_title_test.go

@@ -41,6 +41,15 @@ func TestGenerateAutoTitleCleansResponse(t *testing.T) {
 	if p.req.Thinking != "disabled" || p.req.MaxTokens != 96 || len(p.req.Tools) != 0 {
 		t.Fatalf("request options: %+v", p.req)
 	}
+
+	quoted := &autoTitleProvider{reply: `标题："整理项目设置"`}
+	got, err = GenerateAutoTitle(t.Context(), quoted, "整理项目设置")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got != "整理项目设置" {
+		t.Fatalf("nested quote/prefix cleanup: got %q", got)
+	}
 }
 
 func TestGenerateAutoTitleProviderError(t *testing.T) {