fix: remove relayPool dependency from content loaders

- Remove relayPool from useEffect dependencies in useArticleLoader and useExternalUrlLoader
- This prevents content reloading when relay status changes (going offline/online)
- Content loaders now only re-run when the actual content identifier changes
- Fixes issue where loading skeleton appears when going offline with cached content

src/hooks/useArticleLoader.ts

@@ -311,7 +311,6 @@ export function useArticleLoader({
     }
   }, [
     naddr,
-    relayPool,
     eventStore,
     previewData,
     setSelectedUrl,

src/hooks/useExternalUrlLoader.ts

@@ -167,7 +167,6 @@ export function useExternalUrlLoader({
     }
   }, [
     url,
-    relayPool,
     eventStore,
     cachedUrlHighlights,
     setReaderContent,