perf(bundle): replace plebbit-js imports with local utility, split chunks, fix CLS and rerenders

Eliminate direct @plebbit/plebbit-js (8.7MB) imports from all UI components by replacing
Plebbit.getShortAddress() with a local get-short-address utility. Add Vite manual chunks for
plebbit-js, plebbit-react-hooks, and react-spring/use-gesture. Fix catalog CLS by matching
skeleton to wrapper dimensions. Lazy-load ChallengeModal and ReplyModal. Add failed-URL cache
to useFetchGifFirstFrame, optimize useHide selector, and memoize useFeed options in mod-queue.

src/lib/get-short-address.ts

@@ -0,0 +1,8 @@
+const getShortAddress = (address: string): string => {
+  if (!address) return '';
+  if (address.includes('.')) return address;
+  if (address.length < 20) return '';
+  return address.slice(8, 20);
+};
+
+export default getShortAddress;