feat(learn): add reverse and dictation modes for card review

- Add reverse mode to swap card front/back
- Add dictation mode with TTS audio playback and answer verification
- Add i18n translations for new features in all 8 languages
- Integrate useAudioPlayer hook for TTS playback

messages/fr-FR.json

@@ -295,7 +295,14 @@
       "cardTypeNew": "Nouveau",
       "cardTypeLearning": "Apprentissage",
       "cardTypeReview": "Révision",
-      "cardTypeRelearning": "Réapprentissage"
+      "cardTypeRelearning": "Réapprentissage",
+      "reverse": "Inverser",
+      "dictation": "Dictée",
+      "clickToPlay": "Cliquez pour jouer",
+      "yourAnswer": "Votre réponse",
+      "typeWhatYouHear": "Tapez ce que vous entendez",
+      "correct": "Correct",
+      "incorrect": "Incorrect"
     },
     "page": {
       "unauthorized": "Vous n'êtes pas autorisé à accéder à ce deck"