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/memory_transformer/service.py

@@ -63,7 +63,7 @@ class MemoryTransformerService:
         return self._model
 
     def model_ready(self) -> bool:
-        return WEIGHTS_PATH.is_file() or DEFAULT_WEIGHTS_PATH.is_file()
+        return WEIGHTS_PATH.is_file()
 
     def predict_for_word(
         self,
@@ -86,9 +86,9 @@ class MemoryTransformerService:
         hours_since = _hours_since_review(word, now)
         p_formula = _formula_recall(word, hours_since)
 
-        # 事件少时与艾宾浩斯公式融合，冷启动更稳
+        # 只有真实训练权重才参与融合；默认随机权重仅保留接口兼容性。
         n_events = max(0, valid_len - 1)
-        blend = min(1.0, n_events / 5.0)
+        blend = min(1.0, n_events / 5.0) if self.model_ready() else 0.0
         recall_now = round((blend * p_now + (1.0 - blend) * p_formula) * 100, 1)
 
         if horizon_hours is None: