music(chat): 去掉麻薯人格 prompt，只注入曲目 context

apps/music/frontend/src/views/PlayerView.vue

@@ -233,7 +233,7 @@
       <!-- 右侧 LLM chat 边栏 -->
       <aside v-if="selected" class="chat">
         <header class="chat-head">
-          <span>麻薯 · {{ selected.title.slice(0, 12) }}</span>
+          <span>Chat · {{ selected.title.slice(0, 16) }}</span>
           <button class="chat-clear" @click="onChatClear" title="清空对话">清空</button>
         </header>
         <div ref="chatBodyEl" class="chat-body">

apps/music/src/main.rs

@@ -799,23 +799,22 @@ fn build_chat_context(
         .optional()?;
     let (title, artist, category, lyrics, notes) = row.ok_or(AppError::NotFound)?;
 
-    let mut sys = String::from(
+    // 仅注入当前曲目上下文，不赋予 LLM 任何角色 / 人格。
-        "你是麻薯，一个懂音乐、会乐理、爱聊天的助手。用中文回答，简洁直接，必要时用 markdown。\n\n当前曲目：",
+    let mut sys = String::from("Context: 用户正在查看以下曲目。\n");
-    );
+    sys.push_str(&format!("Title: {}\n", title));
-    sys.push_str(&format!("《{}》", title));
     if let Some(a) = artist.as_deref().filter(|s| !s.is_empty()) {
-        sys.push_str(&format!(" — {}", a));
+        sys.push_str(&format!("Artist: {}\n", a));
     }
     if let Some(c) = category.as_deref().filter(|s| !s.is_empty()) {
-        sys.push_str(&format!("（{}）", c));
+        sys.push_str(&format!("Category: {}\n", c));
     }
     if let Some(n) = notes.as_deref().filter(|s| !s.is_empty()) {
-        sys.push_str(&format!("\n用户笔记：{}", n));
+        sys.push_str(&format!("User notes: {}\n", n));
     }
     if let Some(l) = lyrics.as_deref().filter(|s| !s.is_empty()) {
         // LRC 太长会爆 prompt，截到 4KB
         let trimmed = if l.len() > 4096 { &l[..4096] } else { l };
-        sys.push_str(&format!("\n歌词（截断到 4KB）：\n{}", trimmed));
+        sys.push_str(&format!("Lyrics (truncated to 4KB):\n{}\n", trimmed));
     }
 
     let mut stmt = conn.prepare(