optimized avatar and linkify performance, refined navigation to preserve popups, implemented read marker caching, and added file size limits for saving, minor timetable details changes

lib/state/app/modules/chat/bloc/chat_bloc.dart

@@ -36,6 +36,12 @@ class ChatBloc
   /// popping a stacked chat.
   bool _chatViewActive = false;
 
+  /// True only while a ChatView is actually mounted and tracking its room.
+  /// Read by the notification controller to decide whether an incoming push
+  /// belongs to the chat the user is currently looking at — `currentToken`
+  /// alone would yield false-positives for the last opened chat.
+  bool get hasOpenChat => _chatViewActive;
+
   DateTime _lastTokenSet = DateTime.fromMillisecondsSinceEpoch(0);
 
   ChatBloc({ChatListBloc? chatListBloc}) : _chatListBloc = chatListBloc {
@@ -166,10 +172,19 @@ class ChatBloc
         },
         onNetworkData: (data) {
           // Server-side mark runs unconditionally with the freshly-fetched
-          // maxId. Skipping it on stillCurrent==false would leave the
-          // server cursor wherever a quick navigation away left it.
+          // maxId — skipping it on stillCurrent==false would leave the
+          // server cursor wherever a quick navigation away left it. The
+          // cache check below avoids a redundant POST when the long-poll
+          // (setReadMarker=on) or a previous open already moved the cursor
+          // to this exact id; without it every chat-open did one extra
+          // round-trip even when there was nothing to mark.
           final maxId = _maxMessageId(data);
-          if (maxId > 0) unawaited(sendServerReadMarker(token, maxId));
+          if (maxId > 0) {
+            final cached = _chatListBloc?.lastReadMessageFor(token);
+            if (cached == null || cached < maxId) {
+              unawaited(sendServerReadMarker(token, maxId));
+            }
+          }
           if (!stillCurrent()) return;
           _applyChatResponse(data);
           if (maxId > 0) _chatListBloc?.markRoomAsRead(token, maxId);