perf: reduce startup request fanout

Avoid repeated sidebar session and worktree refreshes
Limit concurrent GitHub PR status checks
Reuse cached worktree root resolution

packages/ui/src/stores/useGitHubPrStatusStore.ts

@@ -1,6 +1,7 @@
 import { create } from 'zustand';
 import { createJSONStorage, persist } from 'zustand/middleware';
 import type { GitHubPullRequestStatus, RuntimeAPIs } from '@/lib/api/types';
+import { mapWithConcurrency } from '@/lib/concurrency';
 import { getSafeStorage } from './utils/safeStorage';
 
 const PR_REVALIDATE_TTL_MS = 90_000;
@@ -10,6 +11,7 @@ const PR_BOOTSTRAP_RETRY_DELAYS_MS = [2_000, 5_000] as const;
 const PR_OPEN_BUSY_INTERVAL_MS = 60_000;
 const PR_OPEN_DEFAULT_INTERVAL_MS = 2 * 60_000;
 const PR_OPEN_STABLE_INTERVAL_MS = 5 * 60_000;
+const PR_STATUS_REFRESH_CONCURRENCY = 4;
 const PR_PERSIST_TTL_MS = 12 * 60 * 60_000;
 const PR_STATUS_STORAGE_KEY = 'openchamber.github-pr-status';
 
@@ -581,7 +583,7 @@ export const useGitHubPrStatusStore = create<GitHubPrStatusStore>()(
             .filter((key): key is string => Boolean(key)),
         ));
 
-        await Promise.all(keys.map((key) => get().refresh(key, options)));
+        await mapWithConcurrency(keys, PR_STATUS_REFRESH_CONCURRENCY, (key) => get().refresh(key, options));
       },
 
       updateStatus: (key, updater) => {

packages/ui/src/stores/useGlobalSessionsStore.ts

@@ -23,7 +23,7 @@ type GlobalSessionsState = {
   archiveSessions: (ids: Iterable<string>, archivedAt?: number) => void;
 };
 
-const PAGE_SIZE = 200;
+const PAGE_SIZE = 500;
 
 let inflightLoad: Promise<LoadResult> | null = null;