Ship native iOS app, Wiki/TTS backend, and skeleton loading UX.

Replace the WebView shell with SwiftUI screens, add account-scoped Wiki and TTS APIs with adaptive review and photo scan support, and keep web/iOS pages usable while data loads asynchronously.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/services/book_service.py

@@ -75,6 +75,7 @@ class BookService:
             "daily_target": row.daily_target,
             "master_required_count": row.master_required_count,
             "weak_wrong_threshold": row.weak_wrong_threshold,
+            "error_clear_correct_count": row.error_clear_correct_count,
             "learn_mode": book.learn_mode,
         }
 
@@ -89,6 +90,8 @@ class BookService:
             row.master_required_count = data["master_required_count"]
         if data.get("weak_wrong_threshold") is not None:
             row.weak_wrong_threshold = data["weak_wrong_threshold"]
+        if data.get("error_clear_correct_count") is not None:
+            row.error_clear_correct_count = data["error_clear_correct_count"]
         db.commit()
         db.refresh(row)
         return self.practice_settings_dict(db, user, book)
@@ -163,6 +166,9 @@ class BookService:
                 wrong_count=0,
                 consecutive_correct_count=0,
                 mastery_score=0,
+                difficulty=5.0,
+                stability_hours=24.0,
+                next_review_at=now,
                 review_due_date=datetime.now(timezone.utc).strftime("%Y-%m-%d"),
                 created_at=now,
             )
@@ -226,6 +232,7 @@ class BookService:
             "daily_target": user_settings.daily_target,
             "master_required_count": user_settings.master_required_count,
             "weak_wrong_threshold": user_settings.weak_wrong_threshold,
+            "error_clear_correct_count": user_settings.error_clear_correct_count,
             "learn_mode": "adaptive",
         }