feat(telegram): improve group handling and default display name to @username

- /lottosettings now opens settings in private DM instead of group
- Bot only reacts to / commands in groups (keyboard buttons ignored)
- Reply keyboard buttons removed from group messages
- Default display name now uses @username instead of 'Anon'
- Users can still manually update display name in settings
- Updated all display name usages to use centralized getDisplayName()

telegram_bot/src/handlers/settings.ts

@@ -35,7 +35,7 @@ export async function handleSettingsCommand(
 
   // Ensure notifications object exists
   const notifications = user.notifications || { ...DEFAULT_NOTIFICATIONS };
-  const displayName = user.displayName || 'Anon';
+  const displayName = stateManager.getDisplayName(user);
 
   await bot.sendMessage(
     chatId,
@@ -83,13 +83,14 @@ export async function handleSettingsCallback(
         });
 
         // Update message
+        const displayName = stateManager.getDisplayName(updatedUser);
         await bot.editMessageText(
-          messages.settings.overview(updatedUser.displayName || 'Anon', updatedUser.notifications),
+          messages.settings.overview(displayName, updatedUser.notifications),
           {
             chat_id: chatId,
             message_id: messageId,
             parse_mode: 'Markdown',
-            reply_markup: getSettingsKeyboard(updatedUser.displayName || 'Anon', updatedUser.notifications),
+            reply_markup: getSettingsKeyboard(displayName, updatedUser.notifications),
           }
         );
       }
@@ -145,8 +146,8 @@ export async function handleDisplayNameInput(
     return;
   }
 
-  // Clean the display name
-  const cleanName = text.replace(/[^\w\s\-_.]/g, '').trim() || 'Anon';
+  // Clean the display name (allow @ for usernames)
+  const cleanName = text.replace(/[^\w\s\-_.@]/g, '').trim() || 'Anon';
 
   await stateManager.updateDisplayName(userId, cleanName);
   logUserAction(userId, 'Set display name', { displayName: cleanName });