feat(cefr): CEFR level testing and automated gap ingestion engine (Task 15)

app/database.py

@@ -202,6 +202,43 @@ def _migrate(conn: sqlite3.Connection):
     """)
     conn.execute("CREATE INDEX IF NOT EXISTS idx_sentence_trans_hash ON sentence_translations(sentence_hash);")
 
+    # Ensure cefr_questions and cefr_progress tables exist
+    conn.execute("""
+    CREATE TABLE IF NOT EXISTS cefr_questions (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        level TEXT NOT NULL,
+        term TEXT NOT NULL COLLATE NOCASE,
+        translation TEXT NOT NULL,
+        pos TEXT DEFAULT '',
+        phonetic TEXT DEFAULT '',
+        sentence TEXT NOT NULL,
+        options_json TEXT NOT NULL,
+        explanation TEXT DEFAULT '',
+        frequency_rank INTEGER DEFAULT 0,
+        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+        UNIQUE(level, term COLLATE NOCASE)
+    );
+    """)
+    conn.execute("CREATE INDEX IF NOT EXISTS idx_cefr_q_level ON cefr_questions(level);")
+    conn.execute("CREATE INDEX IF NOT EXISTS idx_cefr_q_term ON cefr_questions(term COLLATE NOCASE);")
+
+    conn.execute("""
+    CREATE TABLE IF NOT EXISTS cefr_progress (
+        id INTEGER PRIMARY KEY AUTOINCREMENT,
+        user_id INTEGER NOT NULL,
+        question_id INTEGER NOT NULL,
+        level TEXT NOT NULL,
+        is_mastered INTEGER DEFAULT 0,
+        attempts INTEGER DEFAULT 0,
+        mistakes INTEGER DEFAULT 0,
+        last_tested_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+        FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE,
+        FOREIGN KEY (question_id) REFERENCES cefr_questions(id) ON DELETE CASCADE,
+        UNIQUE(user_id, question_id)
+    );
+    """)
+    conn.execute("CREATE INDEX IF NOT EXISTS idx_cefr_prog_user_lvl ON cefr_progress(user_id, level);")
+
     # Auto-seed offline dictionary if empty
     _seed_offline_dictionary(conn)
 
@@ -212,6 +249,13 @@ def _migrate(conn: sqlite3.Connection):
     except Exception:
         pass
 
+    # Seed curated CEFR questions
+    try:
+        from app.cefr import seed_cefr_questions
+        seed_cefr_questions(conn)
+    except Exception:
+        pass
+
 
 def _seed_offline_dictionary(conn: sqlite3.Connection):
     """Seeds the offline dictionary from data/offline_dict.tsv.gz if the table is empty."""