feat: implement Stage 5 (Interactive Reader, EPUB/TXT parser, Bookshelf, Click-to-Translate) and Stage 4.3 (Strict CEFR level calculation)

app/database.py

@@ -64,6 +64,25 @@ def _migrate(conn: sqlite3.Connection):
     conn.execute("CREATE INDEX IF NOT EXISTS idx_srs_user ON srs_logs(user_id);")
     conn.execute("CREATE INDEX IF NOT EXISTS idx_srs_reviewed ON srs_logs(user_id, reviewed_at);")
 
+    # Ensure books table exists
+    conn.execute("""
+    CREATE TABLE IF NOT EXISTS books (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        user_id INTEGER NOT NULL,
+        title TEXT NOT NULL,
+        author TEXT DEFAULT '',
+        source_type TEXT NOT NULL,
+        chapters_json TEXT NOT NULL,
+        current_chapter INTEGER DEFAULT 0,
+        current_position REAL DEFAULT 0,
+        total_words INTEGER DEFAULT 0,
+        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+        updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+        FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+    );
+    """)
+    conn.execute("CREATE INDEX IF NOT EXISTS idx_books_user ON books(user_id);")
+
 
 def init_db():
     config.DB_PATH.parent.mkdir(parents=True, exist_ok=True)
@@ -138,6 +157,22 @@ def init_db():
             response_json TEXT NOT NULL,
             cached_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
         );
+
+        CREATE TABLE IF NOT EXISTS books (
+            id INTEGER PRIMARY KEY AUTOINCREMENT,
+            user_id INTEGER NOT NULL,
+            title TEXT NOT NULL,
+            author TEXT DEFAULT '',
+            source_type TEXT NOT NULL, -- 'epub', 'txt', 'md', 'text'
+            chapters_json TEXT NOT NULL, -- JSON array: [{"title": "Chapter 1", "content": "..."}]
+            current_chapter INTEGER DEFAULT 0,
+            current_position REAL DEFAULT 0,
+            total_words INTEGER DEFAULT 0,
+            created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+            FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE
+        );
+        CREATE INDEX IF NOT EXISTS idx_books_user ON books(user_id);
         """)
         # Apply migrations for pre-existing databases
         _migrate(conn)