refactor(backend): solve copilot comments

backend/requirements.txt

@@ -1,12 +1,12 @@
 aio-pika==9.5.6
 aiormq==6.8.1
 aiosqlite==0.21.0
-alembic
+alembic==1.16.5
 annotated-types==0.7.0
 anyio==4.11.0
 argon2-cffi==23.1.0
 argon2-cffi-bindings==25.1.0
-asyncmy
+asyncmy==0.2.9
 bcrypt==4.3.0
 cffi==2.0.0
 click==8.1.8
@@ -22,6 +22,8 @@ h11==0.16.0
 httptools==0.6.4
 idna==3.10
 makefun==1.16.0
+Mako==1.3.10
+MarkupSafe==3.0.2
 multidict==6.6.4
 pamqp==3.3.0
 propcache==0.3.2
@@ -30,12 +32,14 @@ pycparser==2.23
 pydantic==2.11.9
 pydantic_core==2.33.2
 PyJWT==2.10.1
+PyMySQL==1.1.2
 python-dotenv==1.1.1
 python-multipart==0.0.20
 PyYAML==6.0.2
 sniffio==1.3.1
 SQLAlchemy==2.0.43
 starlette==0.48.0
+tomli==2.2.1
 typing-inspection==0.4.1
 typing_extensions==4.15.0
 uvicorn==0.37.0
@@ -43,4 +47,3 @@ uvloop==0.21.0
 watchfiles==1.1.0
 websockets==15.0.1
 yarl==1.20.1
-pymysql