fix(worktree): read the stale-cleanup ledger through its module

#17857 and #17829 landed minutes apart: one moved staleCleanupInFlight into worktree-create-preparation-stale-cleanup.ts, the other added hasPendingWorktreeCreatePreparations reading it by name. main fails tc:node at the merge.

Claude-Session: https://claude.ai/code/session_01JNnE9qzUZMMnqpZWCqM3nb

src/main/worktree-create-preparation-stale-cleanup.ts

@@ -74,6 +74,10 @@ export async function cleanupStalePreparations(
   }
 }
 
+export function hasStaleCleanupInFlight(): boolean {
+  return staleCleanupInFlight.size > 0
+}
+
 export function resetStalePreparationCleanupForTests(): void {
   staleCleanupInFlight.clear()
 }

src/main/worktree-create-preparation.ts

@@ -26,6 +26,7 @@ import {
 } from './worktree-create-preparation-burst'
 import {
   cleanupStalePreparations,
+  hasStaleCleanupInFlight,
   resetStalePreparationCleanupForTests
 } from './worktree-create-preparation-stale-cleanup'
 import { toHostFilesystemPath } from './host-tree-removal'
@@ -63,7 +64,7 @@ const preparations = new Map<string, PreparationEntry>()
 
 /** A prepared checkout is a create that is either in flight or imminent. */
 export function hasPendingWorktreeCreatePreparations(): boolean {
-  return preparations.size > 0 || staleCleanupInFlight.size > 0
+  return preparations.size > 0 || hasStaleCleanupInFlight()
 }
 
 function pathOps(path: string): Pick<typeof posix, 'dirname' | 'join' | 'normalize'> {