fix: reduce workbench session list load

internal/cloud/server-workbench-http.ts

@@ -17,6 +17,7 @@ import { createWorkbenchReadModel } from "./workbench-read-model.ts";
 import { createWorkbenchTurnProjection, RUNNING_STATUSES, TERMINAL_STATUSES } from "./workbench-turn-projection.ts";
 
 const DEFAULT_PAGE_LIMIT = 50;
+const DEFAULT_SESSION_LIST_LIMIT = 8;
 const MAX_PAGE_LIMIT = 100;
 const DEFAULT_WORKBENCH_SSE_HEARTBEAT_MS = 15000;
 export async function handleWorkbenchReadModelHttp(request, response, url, options = {}) {
@@ -307,7 +308,7 @@ async function authenticateWorkbenchRead(request, response, options) {
 
 async function handleWorkbenchSessionList(response, url, options, actor) {
   if (url.searchParams.has("projectId") || url.searchParams.has("workspaceId")) return sendJson(response, 400, workbenchError("workbench_authority_removed", "Workbench session list is keyed by sessionId only."));
-  const limit = boundedLimit(url.searchParams.get("limit"));
+  const limit = boundedSessionListLimit(url.searchParams.get("limit"));
   const offset = cursorOffset(url.searchParams.get("cursor") ?? url.searchParams.get("after"));
   const includeSessionId = safeSessionId(url.searchParams.get("includeSessionId"));
   const includeRouteId = includeSessionId ?? safeConversationId(url.searchParams.get("includeSessionId"));
@@ -924,6 +925,10 @@ function boundedLimit(value) {
   return Math.min(MAX_PAGE_LIMIT, parsePositiveInteger(value, DEFAULT_PAGE_LIMIT));
 }
 
+function boundedSessionListLimit(value) {
+  return Math.min(MAX_PAGE_LIMIT, parsePositiveInteger(value, DEFAULT_SESSION_LIST_LIMIT));
+}
+
 function cursorOffset(value) {
   const text = textValue(value);
   if (!text) return 0;

web/hwlab-cloud-web/src/stores/workbench.ts

@@ -21,7 +21,7 @@ const TRACE_HYDRATION_MAX_ATTEMPTS = 3;
 const TRACE_HYDRATION_RETRY_DELAY_MS = 700;
 const ACTIVE_TURN_GAP_DELAY_MS = 1_000;
 const ACTIVE_TURN_GAP_MAX_ATTEMPTS = 12;
-const SESSION_LIST_PAGE_LIMIT = 20;
+const SESSION_LIST_PAGE_LIMIT = 8;
 
 interface HydrateOptions {
   sessionId?: string | null;
@@ -68,6 +68,7 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   let realtimeKey = "";
   let realtimeGapTimer: number | null = null;
   let activeTurnGapTimer: number | null = null;
+  const sessionListRefreshInFlight = new Map<string, Promise<void>>();
 
   const activeSession = computed(() => selectActiveSession(serverState.value, explicitSessionId.value));
   const activeSessionSelectionSource = computed(() => activeSelectionSource.value);
@@ -233,7 +234,20 @@ export const useWorkbenchStore = defineStore("workbench", () => {
   }
 
   async function refreshSessions(includeSessionId: string | null = activeSessionId.value): Promise<void> {
-    const response = await api.workbench.sessions({ includeSessionId, limit: currentSessionListLimit() });
+    const requestIncludeSessionId = firstNonEmptyString(includeSessionId);
+    const requestLimit = currentSessionListLimit();
+    const requestKey = `${requestIncludeSessionId ?? ""}|${requestLimit}`;
+    const existing = sessionListRefreshInFlight.get(requestKey);
+    if (existing) return existing;
+    const refresh = refreshSessionsNow(requestIncludeSessionId, requestLimit).finally(() => {
+      if (sessionListRefreshInFlight.get(requestKey) === refresh) sessionListRefreshInFlight.delete(requestKey);
+    });
+    sessionListRefreshInFlight.set(requestKey, refresh);
+    return refresh;
+  }
+
+  async function refreshSessionsNow(includeSessionId: string | null, limit: number): Promise<void> {
+    const response = await api.workbench.sessions({ includeSessionId, limit });
     if (response.ok) {
       const listed = workbenchSessionsFromPayload(response.data);
       const activeSeed = activeSessionListSeed();