Add subscription link field to user model

- Add subscription_link column to users table (nullable, unique)
- Add SUBSCRIPTION_URL to config settings
- Update user creation to include subscription link from Remnawave
- Add support subscription ticket creation with formatted message
- Add "update link" button to main menu
- Refactor support subscription formatting to include user details

db/models/users.py

@@ -1,4 +1,4 @@
-from sqlalchemy import BIGINT
+from sqlalchemy import BIGINT, TEXT
 from sqlalchemy.orm import Mapped, mapped_column
 
 from db.base import Base
@@ -11,3 +11,4 @@ class User(Base):
         BIGINT, nullable=False, unique=True, primary_key=True
     )
     referal_id: Mapped[int] = mapped_column(BIGINT, nullable=True)
+    subscription_link: Mapped[str] = mapped_column(TEXT, nullable=True, unique=True)