feat: Summary UI improvements + PDF fix - Swap short/long labels on summary length slider (RTL: long left, short right) - Remove 'تلخيص النص كاملاً' checkbox and button - Replace single export button with dropdown (TXT/DOCX/PDF) in summary - Hide format toolbar when on summary tab, show on writing tab - Fix PDF export freeze: use foreignObjectRendering:false + lower scale - Add loading toast during PDF export - Add summary DOCX and PDF export functions
