fix: prevent MESSAGE_TOO_LONG in promo groups list

With 20+ promo groups, the full details per group exceeded Telegram's
4096 char limit. Simplified list to one compact line per group with
name and member count. Full details remain in the group detail view.

app/handlers/admin/promo_groups.py

@@ -462,28 +462,17 @@ async def show_promo_groups_menu(
 
         keyboard_rows = []
         for group, member_count in groups:
+            icon = '⭐' if group.is_default else '🎯'
             default_suffix = texts.t('ADMIN_PROMO_GROUPS_DEFAULT_LABEL', ' (базовая)') if group.is_default else ''
-            group_lines = [
-                f'{"⭐" if group.is_default else "🎯"} <b>{group.name}</b>{default_suffix}',
-            ]
-            group_lines.extend(_format_discount_lines(texts, group))
-            group_lines.append(_format_auto_assign_line(texts, group))
-            group_lines.append(
-                texts.t(
-                    'ADMIN_PROMO_GROUPS_MEMBERS_COUNT',
-                    'Участников: {count}',
-                ).format(count=member_count)
-            )
-
-            period_lines = _format_period_discounts_lines(texts, group, db_user.language)
-            group_lines.extend(period_lines)
-            group_lines.append('')
-
-            lines.extend(group_lines)
+            members_label = texts.t(
+                'ADMIN_PROMO_GROUPS_MEMBERS_COUNT',
+                'Участников: {count}',
+            ).format(count=member_count)
+            lines.append(f'{icon} <b>{group.name}</b>{default_suffix} — {members_label}')
             keyboard_rows.append(
                 [
                     types.InlineKeyboardButton(
-                        text=f'{"⭐" if group.is_default else "🎯"} {group.name}',
+                        text=f'{icon} {group.name}',
                         callback_data=f'promo_group_manage_{group.id}',
                     )
                 ]