fix(profile): fetch full profile for avatar decoration to avoid 404 spam

useAvatarDecoration GET /profile/{user}/io.lotus.avatar_decoration returns 404 for
every user without a decoration (most users), which the browser logs as a failed
request — a console 404 per member. Fetch the whole profile (GET /profile/{user},
200 with all MSC4133 fields) and read the decoration field out of it instead. Same
negative-caching behavior; no functional change, just no 404 storm.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/hooks/useAvatarDecoration.ts

@@ -29,7 +29,11 @@ function fetchDecoration(
   const waiters: Array<(val: string | null) => void> = [];
   pending.set(userId, waiters);
 
-  return authedRequest(Method.Get, `/profile/${encodeURIComponent(userId)}/${PROFILE_FIELD}`)
+  // Fetch the WHOLE profile, not the single `/{field}` sub-resource: an unset
+  // field returns 404, which the browser logs as a failed request — a console
+  // 404 for every user without a decoration. The full profile returns 200 with
+  // all fields (incl. custom MSC4133 ones); read the decoration out of it.
+  return authedRequest(Method.Get, `/profile/${encodeURIComponent(userId)}`)
     .then((res) => {
       const val = (res[PROFILE_FIELD] as string | undefined) ?? null;
       cache.set(userId, val);
@@ -37,12 +41,9 @@ function fetchDecoration(
     })
     .catch((err: unknown) => {
       const status = err instanceof MatrixError ? err.httpStatus : undefined;
-      // Definitive rejections — the field is unset (404) or the server won't
-      // serve it (400/403). This is the common case for FEDERATED users whose
-      // homeserver doesn't support extended profiles / rejects the field. Cache
-      // "no decoration" so we never refetch: otherwise every avatar mount
-      // re-requests and floods our homeserver with failing federated profile
-      // lookups (the 403/502 console storm + real HS load).
+      // Definitive rejections (404 unknown user / 403 can't view / 400) — cache
+      // "no decoration" so we never refetch a profile we can't read (otherwise
+      // every avatar mount re-floods our HS with failing federated lookups).
       if (status === 404 || status === 403 || status === 400) {
         cache.set(userId, null);
       } else {