perf(ui): add fingerprint guard to renderUserStrip

Move the data comparison guard into renderUserStrip itself instead
of individual call sites. Prevents unnecessary full DOM rebuilds of
the user/mate strip when called from mate_list, dm_favorites_updated,
or any other message handler with unchanged data.

Author: chadbyte

lib/public/modules/app-projects.js

@@ -229,23 +229,12 @@ export function updateProjectList(msg) {
     }
   }
 
-  // Update user strip (DM targets) - only if user data actually changed
+  // Update user strip (DM targets) - renderUserStrip has its own fingerprint guard
   if (msg.allUsers) {
-    var allUsersJson = JSON.stringify(msg.allUsers);
-    var dmFavJson = msg.dmFavorites ? JSON.stringify(msg.dmFavorites) : _lastDmFavJson;
-    var dmConvJson = msg.dmConversations ? JSON.stringify(msg.dmConversations) : _lastDmConvJson;
-    var userDataChanged = allUsersJson !== _lastAllUsersJson || dmFavJson !== _lastDmFavJson || dmConvJson !== _lastDmConvJson;
-
     _ctx.setCachedAllUsers(msg.allUsers);
     if (msg.dmFavorites) _ctx.setCachedDmFavorites(msg.dmFavorites);
     if (msg.dmConversations) _ctx.setCachedDmConversations(msg.dmConversations);
-
-    if (userDataChanged) {
-      _lastAllUsersJson = allUsersJson;
-      _lastDmFavJson = dmFavJson;
-      _lastDmConvJson = dmConvJson;
-      _ctx.renderUserStrip(msg.allUsers, _ctx.cachedOnlineIds, _ctx.myUserId, _ctx.cachedDmFavorites, _ctx.cachedDmConversations, _ctx.dmUnread, _ctx.dmRemovedUsers, _ctx.cachedMatesList);
-    }
+    _ctx.renderUserStrip(msg.allUsers, _ctx.cachedOnlineIds, _ctx.myUserId, _ctx.cachedDmFavorites, _ctx.cachedDmConversations, _ctx.dmUnread, _ctx.dmRemovedUsers, _ctx.cachedMatesList);
     if (document.body.classList.contains("mate-dm-active") || document.body.classList.contains("wide-view")) {
       var refreshedMyUser = _ctx.cachedAllUsers.find(function (u) { return u.id === _ctx.myUserId; });
       if (refreshedMyUser) {
@@ -271,9 +260,6 @@ export function updateProjectList(msg) {
 var _lastTopbarUserIds = [];
 var _lastProjectsJson = "";
 var _lastRenderedSlug = null;
-var _lastAllUsersJson = "";
-var _lastDmFavJson = "";
-var _lastDmConvJson = "";
 export function renderTopbarPresence(serverUsers) {
   var countEl = document.getElementById("client-count");
   if (!countEl) return;

lib/public/modules/sidebar-mates.js

@@ -19,6 +19,7 @@ var currentDmUserId = null;
 var dmPickerOpen = false;
 var cachedDmRemovedUsers = {};
 var cachedMates = [];
+var _lastUserStripJson = "";
 
 // --- Icon strip tooltip ---
 var iconStripTooltip = null;
@@ -238,6 +239,11 @@ function presenceAvatarUrl(userOrStyle) {
 }
 
 export function renderUserStrip(allUsers, onlineUserIds, myUserId, dmFavorites, dmConversations, dmUnread, dmRemovedUsers, matesList) {
+  // Skip full DOM rebuild if input data hasn't changed
+  var fingerprint = JSON.stringify([allUsers, onlineUserIds, dmFavorites, dmConversations, dmUnread, dmRemovedUsers, matesList]);
+  if (fingerprint === _lastUserStripJson) return;
+  _lastUserStripJson = fingerprint;
+
   cachedMates = matesList || cachedMates || [];
   cachedAllUsers = allUsers || [];
   cachedOnlineUserIds = onlineUserIds || [];