fix(desktop): include more sidebar sessions (#759)

Increase the desktop session list fetch window so noisy observer sessions are less likely to hide real user sessions from the sidebar.

Tested: cd desktop && bun run test -- src/stores/sessionStore.test.ts src/components/layout/Sidebar.test.tsx
Tested: bun run check:desktop
Confidence: high
Scope-risk: narrow

desktop/src/stores/sessionStore.test.ts

@@ -21,6 +21,20 @@ import { useTabStore } from './tabStore'
 
 const initialState = useSessionStore.getState()
 
+function makeSession(id: string, modifiedAt: string, title = id) {
+  return {
+    id,
+    title,
+    createdAt: modifiedAt,
+    modifiedAt,
+    messageCount: 1,
+    projectPath: '/workspace/project',
+    projectRoot: '/workspace/project',
+    workDir: '/workspace/project',
+    workDirExists: true,
+  }
+}
+
 function delay(ms: number) {
   return new Promise((resolve) => setTimeout(resolve, ms))
 }
@@ -136,6 +150,17 @@ describe('sessionStore', () => {
     expect(useTabStore.getState().tabs[0]?.title).toBe('使用bash写一个shell，随便写点什么东西')
   })
 
+  it('requests a large default session page for noisy history directories', async () => {
+    listMock.mockResolvedValue({
+      sessions: [makeSession('session-newest', '2026-05-07T00:00:03.000Z')],
+      total: 474,
+    })
+
+    await useSessionStore.getState().fetchSessions()
+
+    expect(listMock).toHaveBeenCalledWith({ limit: 400 })
+  })
+
   it('ignores stale session list responses when a newer refresh finishes first', async () => {
     const slow = createDeferred<{
       sessions: Array<{

desktop/src/stores/sessionStore.ts

@@ -11,6 +11,8 @@ import type { SessionListItem } from '../types/session'
 import type { PermissionMode } from '../types/settings'
 import { isPlaceholderSessionTitle } from '../lib/sessionTitle'
 
+const SESSION_LIST_LIMIT = 400
+
 type CreateSessionOptions = {
   repository?: CreateSessionRepositoryOptions
   permissionMode?: PermissionMode
@@ -61,22 +63,11 @@ export const useSessionStore = create<SessionStore>((set, get) => ({
     const requestId = ++fetchSessionsRequestId
     set({ isLoading: true, error: null })
     try {
-      const { sessions: raw } = await sessionsApi.list({ project, limit: 100 })
+      const { sessions: raw } = await sessionsApi.list(buildSessionListParams(project))
       if (requestId !== fetchSessionsRequestId) return
       let syncedSessions: SessionListItem[] = []
       set((state) => {
-        const currentById = new Map(state.sessions.map((session) => [session.id, session]))
+        const sessions = mergeSessionList(raw, state.sessions)
-        // Deduplicate by session ID - keep the most recently modified entry.
-        const byId = new Map<string, SessionListItem>()
-        for (const s of raw) {
-          const current = currentById.get(s.id)
-          const candidate = preserveLocalTitle(current, s)
-          const existing = byId.get(s.id)
-          if (!existing || new Date(candidate.modifiedAt) > new Date(existing.modifiedAt)) {
-            byId.set(s.id, candidate)
-          }
-        }
-        const sessions = [...byId.values()]
         syncedSessions = sessions
         return { sessions, isLoading: false }
       })
@@ -237,6 +228,36 @@ function removeIdsFromSet(selected: Set<string>, ids: string[]): Set<string> {
   return next
 }
 
+function buildSessionListParams(project: string | undefined) {
+  return project
+    ? { project, limit: SESSION_LIST_LIMIT }
+    : { limit: SESSION_LIST_LIMIT }
+}
+
+function mergeSessionList(
+  incoming: SessionListItem[],
+  currentForTitle: SessionListItem[],
+): SessionListItem[] {
+  const currentById = new Map(currentForTitle.map((session) => [session.id, session]))
+  const byId = new Map<string, SessionListItem>()
+
+  for (const item of incoming) {
+    const current = currentById.get(item.id)
+    const candidate = preserveLocalTitle(current, item)
+    const existing = byId.get(candidate.id)
+    if (!existing || sessionModifiedTime(candidate) > sessionModifiedTime(existing)) {
+      byId.set(candidate.id, candidate)
+    }
+  }
+
+  return [...byId.values()].sort((a, b) => sessionModifiedTime(b) - sessionModifiedTime(a))
+}
+
+function sessionModifiedTime(session: SessionListItem): number {
+  const timestamp = new Date(session.modifiedAt).getTime()
+  return Number.isFinite(timestamp) ? timestamp : 0
+}
+
 function preserveLocalTitle(
   current: SessionListItem | undefined,
   incoming: SessionListItem,