fix silent onboarding drop-off in /addgamer flow

Set awaiting_addgamer_username as soon as the menu is shown so typing a
username directly (without tapping the button) is handled instead of
being silently ignored. Also stop reporting a valid username as "not
found" when Lichess returns a non-404 error (rate limit/timeout), and
surface an error message if the addgamer menu itself fails to send.

LichessClientTG_bot/bot.py

@@ -340,6 +340,11 @@ class LichessBot:
         logger.info(f"addgamer_start called for user {user_id}")
         
         lang = self.get_user_language_from_update(update)
+        # Mark that we're awaiting a username right away: the menu below is shown
+        # so a user typing the name directly (without tapping a button) is handled
+        # too, instead of being silently ignored by handle_username.
+        if context and hasattr(context, "user_data"):
+            context.user_data['awaiting_addgamer_username'] = True
         try:
             keyboard = [
                 [
@@ -365,6 +370,10 @@ class LichessBot:
             logger.error(f"Error sending addgamer menu: {e}")
             import traceback
             logger.error(traceback.format_exc())
+            try:
+                await update.message.reply_text(t('addgamer_menu_error', lang))
+            except Exception as e2:
+                logger.error(f"Failed to send addgamer menu error message: {e2}")
         # No conversation state returned; handler-based flow
         return
 
@@ -603,6 +612,14 @@ class LichessBot:
         
         # Check if user exists on Lichess
         user_exists = await self.lichess_api.check_user_exists(username)
+        if user_exists is None:
+            # Transient API failure (rate limit, network error, unexpected status) —
+            # don't tell the user the name is wrong, it may well be valid.
+            await update.message.reply_text(
+                t('lichess_temporarily_unavailable', lang) + '\n\n' + t('addgamer_prompt', lang),
+                parse_mode='HTML'
+            )
+            return
         if not user_exists:
             await update.message.reply_text(
                 t('user_not_found', lang, username=username) + '\n\n' + t('addgamer_prompt', lang),