feat: add user preferences migration and context

qwen3-tts-backend/migrate_user_preferences.py

@@ -0,0 +1,37 @@
+import sqlite3
+import json
+import os
+
+DB_PATH = os.path.join(os.path.dirname(__file__), "qwen_tts.db")
+
+def migrate():
+    conn = sqlite3.connect(DB_PATH)
+    cursor = conn.cursor()
+
+    try:
+        cursor.execute("SELECT user_preferences FROM users LIMIT 1")
+        print("Column user_preferences already exists, skipping migration")
+    except sqlite3.OperationalError:
+        print("Adding user_preferences column to users table...")
+        cursor.execute("""
+            ALTER TABLE users
+            ADD COLUMN user_preferences TEXT DEFAULT NULL
+        """)
+
+        cursor.execute("SELECT id FROM users")
+        user_ids = cursor.fetchall()
+
+        default_prefs = json.dumps({"default_backend": "local", "onboarding_completed": False})
+        for (user_id,) in user_ids:
+            cursor.execute(
+                "UPDATE users SET user_preferences = ? WHERE id = ?",
+                (default_prefs, user_id)
+            )
+
+        conn.commit()
+        print(f"Migration completed: Added user_preferences column and initialized {len(user_ids)} users")
+
+    conn.close()
+
+if __name__ == "__main__":
+    migrate()