- add optional collection_photo field to OrderItem type and backend support for pickup photo uploads
- implement in-memory + localStorage cache for order items to eliminate tab-switch loading skeletons
- update service worker to use stale-while-revalidate for navigation requests to reduce perceived lag
- fix LocationTracker to only activate when logged in and hoist to root layout for persistent tracking
- adjust InstallPrompt positioning to avoid overlapping bottom navigation
- throttle map cluster recomputation to reduce unnecessary work during pan/zoom
- clear cached items on logout to prevent cross-driver data leakage
