[ flox1an/nostube ] refactor: use unified event loader from applesauce-loaders v5
Replace createAddressLoader with createEventLoaderForStore in core.ts.
The unified loader automatically routes to the appropriate loader based
on pointer type (EventPointer or AddressPointer) and supports:
- Relay hints via followRelayHints option
- IDB caching via cacheRequest
- Default lookup relays for metadata discovery
Hooks that need custom relay hints (VideoPage, usePlaylistDetails, etc.)