fix(20): IN-04 skip profile-saved toast + refetch on no-op save

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/pwa/src/components/MemberEditorSheet.tsx

@@ -270,11 +270,15 @@ export function MemberEditorSheet({
         payload.displayName = trimmed;
       }
       if (isAdmin !== member.isAdmin) payload.isAdmin = isAdmin;
-      // No-op guard — nothing changed, skip the network call
-      if (Object.keys(payload).length === 0) return;
+      // No-op guard — nothing changed, skip the network call and signal no write
+      // (IN-04: avoids firing the "Profile saved." toast + refetch on a no-op save).
+      if (Object.keys(payload).length === 0) return false;
       await updateMemberProfile(member.id, payload);
+      return true;
     },
-    onSuccess: () => {
+    onSuccess: (changed) => {
+      // IN-04: only surface success feedback when an actual write occurred.
+      if (!changed) return;
       void queryClient.invalidateQueries({ queryKey: ['admin', 'members'] });
       onToast('Profile saved.');
       // Sheet stays open — per-section save (D-05)