feat: 添加获取话题消息数量的方法，优化话题列表和切换话题的反馈信息

src/command/handlers/list_sessions.rs

@@ -65,42 +65,26 @@ async fn handle_list_sessions(
     } else {
         let mut lines = vec![format!("Found {} topic(s):", topics.len())];
         lines.push(String::new());
-        lines.push("┌────┬─────────────────┬──────────────────────┬──────────┬─────────────────┐".to_string());
-        lines.push("│ No │ Topic ID        │ Title                │ Messages │ Last Active     │".to_string());
-        lines.push("├────┼─────────────────┼──────────────────────┼──────────┼─────────────────┤".to_string());
 
         for (idx, topic) in topics.iter().enumerate() {
-            let row_num = idx + 1;
+            let num = idx + 1;
             let is_current = topic.id == current_topic_id;
-            let num_marker = if is_current { " * ".to_string() } else { format!(" {:<2}", row_num) };
+            let marker = if is_current { " *" } else { "" };
 
-            let topic_id_display = if topic.id.len() > 15 {
-                format!("{}...", &topic.id[..12])
-            } else {
-                topic.id.clone()
-            };
-            let title_display = if topic.title.len() > 20 {
-                format!("{}...", &topic.title[..17])
-            } else {
-                topic.title.clone()
-            };
-
-            let last_active = format_time_ago(topic.last_active_at);
+            // 使用辅助方法获取消息数量
+            let msg_count = handler.store
+                .get_topic_message_count(&topic.id)
+                .unwrap_or(0);
 
             lines.push(format!(
-                "│{}│ {:<15} │ {:<20} │ {:<8} │ {:<15} │",
-                num_marker,
-                topic_id_display,
-                title_display,
-                topic.message_count,
-                last_active
+                "{}. {}{} ({})",
+                num, topic.title, marker, msg_count
             ));
         }
 
-        lines.push("└────┴─────────────────┴──────────────────────┴──────────┴─────────────────┘".to_string());
         lines.push(String::new());
         lines.push("* = current topic".to_string());
-        lines.push("Use /use <number> or /use <topic_id> to switch".to_string());
+        lines.push("Use /use <number> to switch".to_string());
 
         lines.join("\n")
     };
@@ -113,24 +97,4 @@ async fn handle_list_sessions(
         .with_metadata("topics", &topics_json)
         .with_metadata("count", &topics.len().to_string())
         .with_metadata("current_topic_id", current_topic_id))
-}
-
-fn format_time_ago(timestamp_ms: i64) -> String {
-    let now = std::time::SystemTime::now()
-        .duration_since(std::time::UNIX_EPOCH)
-        .unwrap()
-        .as_millis() as i64;
-
-    let diff_ms = now - timestamp_ms;
-    let diff_secs = diff_ms / 1000;
-
-    if diff_secs < 60 {
-        "just now".to_string()
-    } else if diff_secs < 3600 {
-        format!("{} mins ago", diff_secs / 60)
-    } else if diff_secs < 86400 {
-        format!("{} hours ago", diff_secs / 3600)
-    } else {
-        format!("{} days ago", diff_secs / 86400)
-    }
 }

src/command/handlers/switch_session.rs

@@ -97,14 +97,19 @@ async fn handle_switch_session(
         }
     }
 
+    // 使用辅助方法获取消息数量
+    let msg_count = handler.store
+        .get_topic_message_count(&target_topic_id)
+        .unwrap_or(0);
+
     let message = format!(
         "✓ Switched to topic: {} ({} messages)",
-        topic.title, topic.message_count
+        topic.title, msg_count
     );
 
     Ok(CommandResponse::success(ctx.request_id)
         .with_message(MessageKind::Notification, &message)
         .with_metadata("topic_id", &topic.id)
         .with_metadata("title", &topic.title)
-        .with_metadata("message_count", &topic.message_count.to_string()))
+        .with_metadata("message_count", &msg_count.to_string()))
 }

src/storage/mod.rs

@@ -1359,6 +1359,11 @@ impl SessionStore {
         Ok(messages)
     }
 
+    /// 获取指定话题的消息数量（动态计算，确保准确）
+    pub fn get_topic_message_count(&self, topic_id: &str) -> Result<usize, StorageError> {
+        self.load_messages_for_topic(topic_id).map(|msgs| msgs.len())
+    }
+
     pub fn load_all_messages(&self, session_id: &str) -> Result<Vec<ChatMessage>, StorageError> {
         let conn = self.conn.lock().expect("session db mutex poisoned");
         load_messages_after(&conn, session_id, 0)