perf(topics): 新建/删除/重命名话题同样走 spawn_blocking 统一提速

- 抽取 list_topic_summaries_blocking 公共 helper（list_topics + build_topic_summaries 在 blocking 线程池执行）
- create/delete/rename 三个话题命令返回侧边栏刷新列表时统一走 helper，DB 查询不再阻塞 tokio worker
- 结合增量统计列，四个话题命令的列表构建均从 O(全部消息) 降为 O(话题数)

src/command/handlers/delete_topic.rs

@@ -1,7 +1,6 @@
 use crate::command::Command;
 use crate::command::context::CommandContext;
 use crate::command::handler::{CommandHandler, CommandMetadata};
-use crate::command::handlers::list_topics::build_topic_summaries;
 use crate::command::response::{CommandError, CommandResponse, MessageKind};
 use crate::gateway::session::SessionManager;
 use crate::storage::SessionStore;
@@ -82,12 +81,12 @@ async fn handle_delete_topic(
         .map_err(|e| CommandError::new("DELETE_TOPIC_ERROR", e.to_string()))?;
 
     // 查询更新后的话题列表，返回给前端刷新侧边栏
-    let topics = handler
-        .store
-        .list_topics(session_id)
-        .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?;
-
-    let topic_summaries = build_topic_summaries(handler.store.as_ref(), topics)?;
+    let topic_summaries =
+        crate::command::handlers::list_topics::list_topic_summaries_blocking(
+            handler.store.clone(),
+            session_id,
+        )
+        .await?;
 
     let topics_json = serde_json::to_string(&topic_summaries)
         .map_err(|e| CommandError::new("SERIALIZE_ERROR", e.to_string()))?;

src/command/handlers/list_topics.rs

@@ -97,6 +97,28 @@ pub fn build_topic_summaries(
     Ok(summaries)
 }
 
+/// 在 blocking 线程池中执行 list_topics + build_topic_summaries。
+///
+/// 同步 rusqlite 查询不得直接跑在 tokio worker 上，否则大库查询会饿死
+/// 同运行时上的其他任务。list / create / delete / rename 四个话题命令
+/// 都返回完整的 TopicSummary 列表供前端刷新侧边栏，统一走本 helper。
+pub async fn list_topic_summaries_blocking(
+    store: Arc<SessionStore>,
+    session_id: &str,
+) -> Result<Vec<TopicSummary>, CommandError> {
+    let session_id_bg = session_id.to_string();
+    tokio::task::spawn_blocking(
+        move || -> Result<Vec<TopicSummary>, CommandError> {
+            let topics = store
+                .list_topics(&session_id_bg)
+                .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?;
+            build_topic_summaries(store.as_ref(), topics)
+        },
+    )
+    .await
+    .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?
+}
+
 /// 列出 Session 的 Topics 命令处理器
 pub struct ListTopicsCommandHandler {
     store: Arc<SessionStore>,
@@ -139,20 +161,8 @@ async fn handle_list_topics(
     session_id: String,
     ctx: CommandContext,
 ) -> Result<CommandResponse, CommandError> {
-    // 同步 rusqlite 查询移入 blocking 线程池，避免大库查询阻塞 tokio worker
-    // 饿死同连接上的其他 WS 命令（话题列表刷新是高频操作）。
-    let store = handler.store.clone();
-    let session_id_bg = session_id.clone();
-    let summaries = tokio::task::spawn_blocking(
-        move || -> Result<Vec<TopicSummary>, CommandError> {
-            let topics = store
-                .list_topics(&session_id_bg)
-                .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?;
-            build_topic_summaries(store.as_ref(), topics)
-        },
-    )
-    .await
-    .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))??;
+    let summaries =
+        list_topic_summaries_blocking(handler.store.clone(), &session_id).await?;
 
     let topics_json = serde_json::to_string(&summaries)
         .map_err(|e| CommandError::new("SERIALIZE_ERROR", e.to_string()))?;

src/command/handlers/rename_topic.rs

@@ -1,7 +1,6 @@
 use crate::command::Command;
 use crate::command::context::CommandContext;
 use crate::command::handler::{CommandHandler, CommandMetadata};
-use crate::command::handlers::list_topics::build_topic_summaries;
 use crate::command::response::{CommandError, CommandResponse, MessageKind};
 use crate::storage::SessionStore;
 use async_trait::async_trait;
@@ -84,11 +83,12 @@ async fn handle_rename_topic(
 
     // 标题未变化时直接返回当前列表，避免无意义写入
     if old_display == trimmed_title {
-        let topics = handler
-            .store
-            .list_topics(session_id)
-            .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?;
-        let topic_summaries = build_topic_summaries(handler.store.as_ref(), topics)?;
+        let topic_summaries =
+            crate::command::handlers::list_topics::list_topic_summaries_blocking(
+                handler.store.clone(),
+                session_id,
+            )
+            .await?;
         let topic_summaries_json = serde_json::to_string(&topic_summaries)
             .map_err(|e| CommandError::new("SERIALIZE_ERROR", e.to_string()))?;
 
@@ -110,12 +110,12 @@ async fn handle_rename_topic(
         .map_err(|e| CommandError::new("RENAME_TOPIC_ERROR", e.to_string()))?;
 
     // 查询更新后的话题列表，返回给前端刷新侧边栏
-    let topics = handler
-        .store
-        .list_topics(session_id)
-        .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?;
-
-    let topic_summaries = build_topic_summaries(handler.store.as_ref(), topics)?;
+    let topic_summaries =
+        crate::command::handlers::list_topics::list_topic_summaries_blocking(
+            handler.store.clone(),
+            session_id,
+        )
+        .await?;
     let topic_summaries_json = serde_json::to_string(&topic_summaries)
         .map_err(|e| CommandError::new("SERIALIZE_ERROR", e.to_string()))?;
 

src/command/handlers/session.rs

@@ -1,7 +1,6 @@
 use crate::command::Command;
 use crate::command::context::CommandContext;
 use crate::command::handler::{CommandHandler, CommandMetadata};
-use crate::command::handlers::list_topics::build_topic_summaries;
 use crate::command::response::{CommandError, CommandResponse, MessageKind};
 use crate::gateway::session::SessionManager;
 use crate::storage::SessionStore;
@@ -104,12 +103,12 @@ async fn handle_create_session(
     }
 
     // Query the full topic list so the frontend sidebar can update
-    let topics = handler
-        .store
-        .list_topics(session_id)
-        .map_err(|e| CommandError::new("LIST_TOPICS_ERROR", e.to_string()))?;
-
-    let topic_summaries = build_topic_summaries(handler.store.as_ref(), topics)?;
+    let topic_summaries =
+        crate::command::handlers::list_topics::list_topic_summaries_blocking(
+            handler.store.clone(),
+            session_id,
+        )
+        .await?;
 
     let topics_json = serde_json::to_string(&topic_summaries)
         .map_err(|e| CommandError::new("SERIALIZE_ERROR", e.to_string()))?;