Add word-book practice, iOS app shell, and fix embedded WebView blank screen.

Ship dual-track learning (daily accumulation vs textbook),沪教/商务词书 APIs and UI, native iOS wrapper with bundled H5, and production book import on deploy.

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

backend/models.py

@@ -1,4 +1,4 @@
-from sqlalchemy import Column, ForeignKey, Integer, String, Text
+from sqlalchemy import Column, ForeignKey, Integer, String, Text, UniqueConstraint
 
 from database import Base
 
@@ -12,11 +12,54 @@ class User(Base):
     created_at = Column(String(32), nullable=False)
 
 
+class WordBook(Base):
+    """全局词书目录（部署时导入）。"""
+
+    __tablename__ = "word_books"
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    slug = Column(String(64), unique=True, nullable=False, index=True)
+    title = Column(String(128), nullable=False)
+    description = Column(Text, nullable=True)
+    level = Column(String(32), nullable=False)
+    word_count = Column(Integer, nullable=False, default=0)
+    unit_count = Column(Integer, nullable=False, default=0)
+    sort_order = Column(Integer, nullable=False, default=0)
+    daily_target = Column(Integer, nullable=False, default=15)
+    master_required_count = Column(Integer, nullable=False, default=4)
+    weak_wrong_threshold = Column(Integer, nullable=False, default=2)
+    learn_mode = Column(String(32), nullable=False, default="sequential")
+    is_published = Column(Integer, nullable=False, default=1)
+
+
+class WordBookEntry(Base):
+    __tablename__ = "word_book_entries"
+    __table_args__ = (UniqueConstraint("book_id", "lemma_en", name="uq_book_lemma"),)
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    book_id = Column(Integer, ForeignKey("word_books.id"), nullable=False, index=True)
+    unit = Column(Integer, nullable=False, default=1)
+    unit_title = Column(String(128), nullable=True)
+    sort_index = Column(Integer, nullable=False, index=True)
+    lemma_en = Column(String(128), nullable=False)
+    zh = Column(String(256), nullable=False)
+    phonetic = Column(String(128), nullable=True)
+    example_en = Column(Text, nullable=True)
+    example_cn = Column(Text, nullable=True)
+
+
 class Word(Base):
     __tablename__ = "words"
+    __table_args__ = (
+        UniqueConstraint(
+            "user_id", "book_id", "source_text", "target_text", name="uq_user_book_word"
+        ),
+    )
 
     id = Column(Integer, primary_key=True, autoincrement=True)
     user_id = Column(Integer, ForeignKey("users.id"), nullable=False, index=True)
+    book_id = Column(Integer, nullable=False, default=0, index=True)
+    book_entry_id = Column(Integer, ForeignKey("word_book_entries.id"), nullable=True)
     source_text = Column(String(500), nullable=False)
     target_text = Column(String(500), nullable=False)
     source_lang = Column(String(8), nullable=False)
@@ -58,6 +101,21 @@ class UserSettings(Base):
     daily_target = Column(Integer, nullable=False, default=20)
     master_required_count = Column(Integer, nullable=False, default=3)
     weak_wrong_threshold = Column(Integer, nullable=False, default=3)
+    active_book_id = Column(Integer, ForeignKey("word_books.id"), nullable=True)
+
+
+class UserBookSettings(Base):
+    """用户对某本词书的练习参数（每本书独立保存）。"""
+
+    __tablename__ = "user_book_settings"
+    __table_args__ = (UniqueConstraint("user_id", "book_id", name="uq_user_book_settings"),)
+
+    id = Column(Integer, primary_key=True, autoincrement=True)
+    user_id = Column(Integer, ForeignKey("users.id"), nullable=False, index=True)
+    book_id = Column(Integer, ForeignKey("word_books.id"), nullable=False, index=True)
+    daily_target = Column(Integer, nullable=False, default=12)
+    master_required_count = Column(Integer, nullable=False, default=3)
+    weak_wrong_threshold = Column(Integer, nullable=False, default=2)
 
 
 class DictionaryEntry(Base):