fix(storage): 清理旧版本遗留的空 cli 会话并降级会话列表日志

- 早期版本每次 WebSocket 连接都会新建一个 cli 通道空会话（CLI Session xxxxxxxx），长期运行积累大量空壳记录，导致会话列表冗长、网关日志逐条刷屏

- 新增 user_version=3 一次性迁移：删除无消息/话题/待办/技能事件的 cli 空会话，有真实内容的会话不受影响（事务包裹，含回归测试）

- ws.rs 会话列表逐条日志由 INFO 降级为 debug，仅保留条数汇总

src/gateway/ws.rs

@@ -238,9 +238,17 @@ async fn handle_socket(ws: WebSocket, state: Arc<GatewayState>) {
         websocket_sessions.sort_by_key(|s| -(s.last_active_at));
     }
 
-    tracing::info!("Sending {} sessions to client", websocket_sessions.len());
+    tracing::info!(
+        session_count = websocket_sessions.len(),
+        "Sending session list to client"
+    );
     for s in &websocket_sessions {
-        tracing::info!("  - {}: {} (channel: {})", s.id, s.title, s.channel_name);
+        tracing::debug!(
+            session_id = %s.id,
+            title = %s.title,
+            channel = %s.channel_name,
+            "Session list entry"
+        );
     }
 
     let session_summaries: Vec<crate::protocol::SessionSummary> = websocket_sessions

src/storage/migrations.rs

@@ -383,6 +383,46 @@ fn repair_session_id_prefix_pollution_inner(conn: &Connection) -> Result<(), Sto
     Ok(())
 }
 
+/// 清理历史遗留的空 cli 会话（user_version 3，一次性迁移）。
+///
+/// 早期版本每次 WebSocket 连接建立都会新建一个 cli 通道空会话
+/// （自动标题 "CLI Session xxxxxxxx"），长期运行后 sessions 表积累大量
+/// 空壳记录：它们会被并入发送给前端的会话列表，也在网关日志中逐条打印。
+/// 本迁移删除没有任何消息、话题、待办、技能事件的 cli 会话（纯空壳），
+/// 有真实内容的会话不受影响。事务包裹，通过 PRAGMA user_version 仅执行一次。
+pub(super) fn cleanup_legacy_empty_cli_sessions(conn: &mut Connection) -> Result<(), StorageError> {
+    const EMPTY_CLI_CLEANUP_VERSION: i64 = 3;
+
+    let current_version: i64 = conn.query_row("PRAGMA user_version", [], |row| row.get(0))?;
+    if current_version >= EMPTY_CLI_CLEANUP_VERSION {
+        return Ok(());
+    }
+
+    let tx = conn.transaction()?;
+    let deleted = tx.execute(
+        "DELETE FROM sessions
+         WHERE channel_name = 'cli'
+           AND NOT EXISTS (SELECT 1 FROM messages m WHERE m.session_id = sessions.id)
+           AND NOT EXISTS (SELECT 1 FROM topics t WHERE t.session_id = sessions.id)
+           AND NOT EXISTS (SELECT 1 FROM todos d WHERE d.session_id = sessions.id)
+           AND NOT EXISTS (SELECT 1 FROM skill_events s WHERE s.session_id = sessions.id)",
+        [],
+    )?;
+    if deleted > 0 {
+        tracing::info!(
+            deleted_count = deleted,
+            "Cleaned up legacy empty cli sessions"
+        );
+    }
+    tx.execute(
+        &format!("PRAGMA user_version = {EMPTY_CLI_CLEANUP_VERSION}"),
+        [],
+    )?;
+    tx.commit()?;
+
+    Ok(())
+}
+
 pub(super) fn ensure_todos_schema(conn: &Connection) -> Result<(), StorageError> {
     let table_exists: bool = conn
         .query_row(

src/storage/mod.rs

@@ -238,6 +238,7 @@ impl SessionStore {
         ensure_todos_schema(&conn)?;
         ensure_pending_subagents_schema(&conn)?;
         repair_session_id_prefix_pollution(&mut conn)?;
+        cleanup_legacy_empty_cli_sessions(&mut conn)?;
 
         drop(conn);
 

src/storage/tests.rs

@@ -794,3 +794,33 @@ fn test_repair_session_id_prefix_pollution() {
     assert_eq!(store.get_session("abc").unwrap().unwrap().message_count, 2);
     assert_eq!(store.list_sessions("websocket", false).unwrap().len(), 2);
 }
+
+#[test]
+fn test_cleanup_legacy_empty_cli_sessions() {
+    let store = SessionStore::in_memory().unwrap();
+
+    // 空 cli 会话（旧版本遗留的空壳）：应被删除
+    let empty = store.create_cli_session(None).unwrap();
+    // 有消息的 cli 会话：必须保留
+    let with_data = store.create_cli_session(None).unwrap();
+    store
+        .append_message(&with_data.id, &ChatMessage::user("hello"))
+        .unwrap();
+    // 空 websocket 会话：不在 cli 清理范围内
+    let ws = store.ensure_channel_session("websocket", "chat-1").unwrap();
+
+    let mut conn = store.pool.get().unwrap();
+    // from_connection 已把 user_version 推到 3，回退到 2 模拟"尚未清理"
+    conn.execute("PRAGMA user_version = 2", []).unwrap();
+
+    super::migrations::cleanup_legacy_empty_cli_sessions(&mut conn).unwrap();
+
+    assert!(store.get_session(&empty.id).unwrap().is_none());
+    assert!(store.get_session(&with_data.id).unwrap().is_some());
+    assert!(store.get_session(&ws.id).unwrap().is_some());
+
+    // 幂等：版本守卫使第二次调用直接跳过，已有会话不受影响
+    super::migrations::cleanup_legacy_empty_cli_sessions(&mut conn).unwrap();
+    assert!(store.get_session(&with_data.id).unwrap().is_some());
+    assert!(store.get_session(&ws.id).unwrap().is_some());
+}