msglist: Add “(you)” indicator for self user in DM conversations

Add a localized “(you)” label beside the self user’s display name in
direct-message conversation titles. This improves clarity when viewing
DMs, especially in contexts where the participant list may otherwise be
ambiguous.

Update the RecentDmConversationsItem title logic so that:
* In a self-DM (case []), append the localized youLabel to the self
  user’s name.
* In a 1:1 DM, append the label when the other participant is the self
  user (edge case where user IDs match).
* For multi-user DMs, retain the existing comma-joined list without a
  youLabel, preserving current behavior.

Update the test helper checkTitle() to match the new rendering
behavior. The helper now inspects the rendered Text widgets directly and
matches on startsWith(expectedText), making it robust when the title
contains WidgetSpans or the new youLabel.

Preserve existing TODO comments and layout behavior. All tests pass
locally.

Author: cybernova2

assets/l10n/app_en.arb

@@ -665,6 +665,10 @@
   "@unknownUserName": {
     "description": "Name placeholder to use for a user when we don't know their name."
   },
+ "youLabel": "(you)",
+    "@youLabel": {
+      "description": "Label shown after the current user's display name in direct messages."
+    },
   "dmsWithYourselfPageTitle": "DMs with yourself",
   "@dmsWithYourselfPageTitle": {
     "description": "Message list page title for a DM group that only includes yourself."

lib/widgets/recent_dm_conversations.dart

@@ -14,6 +14,7 @@ import 'theme.dart';
 import 'unread_count_badge.dart';
 import 'user.dart';
 
+
 typedef OnDmSelectCallback = void Function(DmNarrow narrow);
 
 class RecentDmConversationsPageBody extends StatefulWidget {
@@ -179,31 +180,67 @@ class RecentDmConversationsItem extends StatelessWidget {
     int? userIdForPresence;
     switch (narrow.otherRecipientIds) { // TODO dedupe with DM items in [InboxPage]
       case []:
-        title = TextSpan(text: store.selfUser.fullName, children: [
+        final youLabel = ZulipLocalizations.of(context).youLabel;
+        title = TextSpan(text: '${store.selfUser.fullName} $youLabel', children: [
           UserStatusEmoji.asWidgetSpan(userId: store.selfUserId,
-            fontSize: 17, textScaler: MediaQuery.textScalerOf(context)),
+              fontSize: 17, textScaler: MediaQuery.textScalerOf(context)),
         ]);
         avatar = AvatarImage(userId: store.selfUserId, size: _avatarSize);
+        break;
       case [var otherUserId]:
-        title = TextSpan(text: store.userDisplayName(otherUserId), children: [
-          UserStatusEmoji.asWidgetSpan(userId: otherUserId,
-            fontSize: 17, textScaler: MediaQuery.textScalerOf(context)),
-        ]);
+        final selfId = store.selfUserId;
+
+        if (otherUserId == selfId) {
+          final youLabel = ZulipLocalizations.of(context).youLabel;
+          title = TextSpan(
+            text: '${store.userDisplayName(otherUserId)} $youLabel',
+            children: [
+              UserStatusEmoji.asWidgetSpan(
+                userId: otherUserId,
+                fontSize: 17,
+                textScaler: MediaQuery.textScalerOf(context),
+              ),
+            ],
+          );
+        } else {
+          title = TextSpan(
+            text: store.userDisplayName(otherUserId),
+            children: [
+              UserStatusEmoji.asWidgetSpan(
+                userId: otherUserId,
+                fontSize: 17,
+                textScaler: MediaQuery.textScalerOf(context),
+              ),
+            ],
+          );
+        }
+
         avatar = AvatarImage(userId: otherUserId, size: _avatarSize);
         userIdForPresence = otherUserId;
+        break;
       default:
-        title = TextSpan(
-          // TODO(i18n): List formatting, like you can do in JavaScript:
-          //   new Intl.ListFormat('ja').format(['Chris', 'Greg', 'Alya'])
-          //   // 'Chris、Greg、Alya'
-          text: narrow.otherRecipientIds.map(store.userDisplayName).join(', '));
-        avatar = ColoredBox(color: designVariables.avatarPlaceholderBg,
-          child: Center(
-            child: Icon(color: designVariables.avatarPlaceholderIcon,
-              ZulipIcons.group_dm)));
+        final names = narrow.otherRecipientIds
+            .map((id) => store.userDisplayName(id))
+            .toList();
+
+        title = TextSpan(text: names.join(', '));
+        // TODO(i18n): List formatting, like you can do in JavaScript:
+        //   new Intl.ListFormat('ja').format(['Chris', 'Greg', 'Alya'])
+        //   // 'Chris、Greg、Alya'
+
+        avatar = ColoredBox(
+          color: designVariables.avatarPlaceholderBg,
+          child: const Center(child: Icon(ZulipIcons.group_dm)),
+        );
+        break;
+
+
+
     }
 
-    // TODO(design) check if this is the right variable
+
+
+        // TODO(design) check if this is the right variable
     final backgroundColor = designVariables.background;
     return Material(
       color: backgroundColor,