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

services/rw.py

@@ -26,6 +26,7 @@ class RWUserInfo:
     hwid_device_limit: Optional[int]  # None = unlimited
     active_squads: list[dict]  # [{"uuid": "...", "name": "..."}]
     description: Optional[str]
+    short_uuid: str
 
 
 # ─────────────────────────────────────────────────────────────────
@@ -61,6 +62,7 @@ def _parse_user(user_dto) -> RWUserInfo:
         hwid_device_limit=user_dto.hwid_device_limit,
         active_squads=active_squads,
         description=user_dto.description,
+        short_uuid=user_dto.short_uuid,
     )