SMM X PRO V27 - Support + Maintenance Final Update

1. Live Support composer fixed for mobile + desktop:
   - Attachment control is a real label/file-picker control, not JS-only.
   - Keyboard accessible (Enter/Space).
   - Photo size validation before upload.
   - AJAX requests keep same-origin credentials and require JSON.
   - Server errors are shown instead of a generic silent connection failure.
   - Existing image preview/viewer remains responsive.

2. Support notifications:
   - User text support messages continue to notify the configured notification channel.
   - User photo support messages now send the actual Telegram photo to the configured notification channel, with user/caption details.
   - If the photo notification fails, the text notification is used as fallback.

3. Maintenance mode:
   - Maintenance now blocks normal bot use even for a first-time /start user.
   - Support remains available as the escape path.
   - Admin Settings > Availability now has 3 editable maintenance lines.
   - Each line supports: Emoji ID before + text + Emoji ID after.
   - Default IDs/text are the IDs supplied by the owner.
   - Pressing Turn bot OFF saves the current maintenance text/emoji fields first, then enables maintenance.
   - While OFF, users receive the configured custom-emoji maintenance message.

Default maintenance lines:
4949628832849068770 | বর্তমান আমাদের বট টা বন্ধ রাখা হয়েছে | 5974083768233760323
5168422700359615159 | দয়া করে কিছুক্ষণ পরে আবার চেষ্টা করুন। | 5231265076991769644
5807952667992920776 | জরুরি প্রয়োজন হলে Support ব্যবহার করতে পারেন। | 5193202823411546657