perf: 优化 Agent 流式会话处理

- 合并流式通知与持久化写入，限制浏览器会话缓存

- 增量投影轮次事件并稳定关联异步工具任务

easyflow-ui-admin/app/src/views/ai/agent-chat/agentChatRuntimeManager.ts

@@ -64,10 +64,15 @@ interface StartOptions {
 }
 
 const STORAGE_VERSION = 2;
+const STREAM_NOTIFY_INTERVAL_MS = 50;
+const STREAM_PERSIST_INTERVAL_MS = 300;
+const MAX_RUNTIME_SESSIONS_PER_IDENTITY = 10;
 
 const sessions = new Map<string, RuntimeSessionState>();
 const listeners = new Set<() => void>();
 const latestSessionIds = new Map<string, string>();
+const persistTimers = new Map<string, ReturnType<typeof setTimeout>>();
+let notifyTimer: ReturnType<typeof setTimeout> | undefined;
 
 function clone<T>(value: T): T {
   const serialized = JSON.stringify(value);
@@ -108,6 +113,24 @@ function notify() {
   }
 }
 
+function notifyNow() {
+  if (notifyTimer) {
+    clearTimeout(notifyTimer);
+    notifyTimer = undefined;
+  }
+  notify();
+}
+
+function scheduleNotify() {
+  if (notifyTimer || listeners.size === 0) {
+    return;
+  }
+  notifyTimer = setTimeout(() => {
+    notifyTimer = undefined;
+    notify();
+  }, STREAM_NOTIFY_INTERVAL_MS);
+}
+
 function persistSession(state: RuntimeSessionState) {
   const storage = safeSessionStorage();
   if (!storage) {
@@ -118,7 +141,7 @@ function persistSession(state: RuntimeSessionState) {
     agentName: state.agentName,
     completed: state.completed,
     error: state.error,
-    items: clone(state.items),
+    items: state.items,
     prompt: state.prompt,
     roundId: state.roundId,
     sessionId: state.sessionId,
@@ -136,6 +159,82 @@ function persistSession(state: RuntimeSessionState) {
   }
 }
 
+function cancelPersistTimer(scopedSessionKey: string) {
+  const timer = persistTimers.get(scopedSessionKey);
+  if (!timer) {
+    return;
+  }
+  clearTimeout(timer);
+  persistTimers.delete(scopedSessionKey);
+}
+
+function removeSessionCache(
+  scopedSessionKey: string,
+  state: RuntimeSessionState,
+) {
+  cancelPersistTimer(scopedSessionKey);
+  sessions.delete(scopedSessionKey);
+  try {
+    safeSessionStorage()?.removeItem(
+      storageKey(state.identity, state.sessionId),
+    );
+  } catch {
+    // 本地缓存清理失败不影响服务端会话。
+  }
+}
+
+function pruneRuntimeSessions(identity: string, currentSessionId: string) {
+  const scopedSessions = [...sessions.entries()]
+    .filter(([, session]) => session.identity === identity)
+    .sort((first, second) => second[1].updatedAt - first[1].updatedAt);
+  if (scopedSessions.length <= MAX_RUNTIME_SESSIONS_PER_IDENTITY) {
+    return;
+  }
+  const protectedKeys = new Set(
+    scopedSessions
+      .filter(
+        ([, session]) =>
+          session.sending || session.sessionId === currentSessionId,
+      )
+      .map(([key]) => key),
+  );
+  let retainedCount = protectedKeys.size;
+  for (const [key, session] of scopedSessions) {
+    if (protectedKeys.has(key)) {
+      continue;
+    }
+    if (retainedCount < MAX_RUNTIME_SESSIONS_PER_IDENTITY) {
+      retainedCount += 1;
+      continue;
+    }
+    removeSessionCache(key, session);
+  }
+}
+
+function touchState(state: RuntimeSessionState) {
+  state.updatedAt = Date.now();
+  latestSessionIds.set(state.identity, state.sessionId);
+  sessions.set(sessionKey(state.identity, state.sessionId), state);
+}
+
+function scheduleStateUpdate(state: RuntimeSessionState) {
+  touchState(state);
+  const scopedSessionKey = sessionKey(state.identity, state.sessionId);
+  if (!persistTimers.has(scopedSessionKey)) {
+    persistTimers.set(
+      scopedSessionKey,
+      setTimeout(() => {
+        persistTimers.delete(scopedSessionKey);
+        const current = sessions.get(scopedSessionKey);
+        if (current) {
+          persistSession(current);
+        }
+      }, STREAM_PERSIST_INTERVAL_MS),
+    );
+  }
+  scheduleNotify();
+}
+
 function restoreSession(identity: string, sessionId: string) {
   if (!identity) {
     return undefined;
@@ -179,11 +278,11 @@ function restoreSession(identity: string, sessionId: string) {
 }
 
 function upsertState(state: RuntimeSessionState) {
-  state.updatedAt = Date.now();
-  latestSessionIds.set(state.identity, state.sessionId);
-  sessions.set(sessionKey(state.identity, state.sessionId), state);
+  touchState(state);
+  cancelPersistTimer(sessionKey(state.identity, state.sessionId));
   persistSession(state);
-  notify();
+  pruneRuntimeSessions(state.identity, state.sessionId);
+  notifyNow();
 }
 
 function runningSession(identity = identityScope()) {
@@ -272,11 +371,12 @@ function replaceAcceptedImages(
 onAgentChatCacheClear((identity) => {
   for (const [key, session] of sessions) {
     if (session.identity === identity) {
+      cancelPersistTimer(key);
       sessions.delete(key);
     }
   }
   latestSessionIds.delete(identity);
-  notify();
+  notifyNow();
 });
 
 export const agentChatRuntimeManager = {
@@ -383,7 +483,7 @@ export const agentChatRuntimeManager = {
             void options.onInputAccepted?.();
           }
           applyAgentSseEnvelope(current.items, envelope, { roundId });
-          upsertState(current);
+          scheduleStateUpdate(current);
         },
       },
     );