feat(rtl): rendu droite-a-gauche complet pour Word, PowerPoint, Excel et PDF

- source unique RTL_LANGUAGES/is_rtl dans core/languages.py (fin des 3 copies)
- Word: bidi partout (corps, tableaux bidiVisual, notes/fin/commentaires,
  zones de texte, 6 zones d'en-tetes/pieds), insertion OOXML ordonnee,
  polices cs elargies aux 11 langues
- PowerPoint: alignements explicites preserves, notes du presentateur,
  indice de police <a:cs> insert a sa place
- Excel: feuilles affichees de droite a gauche, feuilles graphiques ignorees
- PDF: faconnage bidi (arabic-reshaper + python-bidi), polices par ecriture
  (arabe/hebreu), TTF enregistree pour le PDF recompose
- 46 tests nouveaux (tests/test_translators/test_rtl_layout.py), 253 au total

scripts/debug_smart_fit_trace.py

@@ -11,7 +11,7 @@ spec.loader.exec_module(pdf_mod)
 
 original_write = pdf_mod.PDFTranslator._write_translated_block
 
-def debug_write(self, page, block, font_path, is_rtl):
+def debug_write(self, page, block, font_path, rtl_target):
     target_size = block['font_size']
     original_rect = fitz.Rect(block['bbox'])
     page_rect = page.rect
@@ -40,7 +40,7 @@ def debug_write(self, page, block, font_path, is_rtl):
     text = block['translated'][:40]
     is_heading_str = "HEAD" if is_heading else "BODY"
     print(f"  [{is_heading_str}] text={text!r} | orig={original_rect.width:.0f}x{original_rect.height:.0f} | exp_v={expanded_v.width:.0f}x{expanded_v.height:.0f} | size={target_size}", flush=True)
-    result = original_write(self, page, block, font_path, is_rtl)
+    result = original_write(self, page, block, font_path, rtl_target)
     print(f"      result: {result}", flush=True)
     return result