fix: Resolve Vaultwarden unprivileged port binding and update Admin Token docs

vaultwarden/SETUP.md

@@ -32,6 +32,11 @@ Vaultwarden is a lightweight, community-driven server implementation of the Bitw
 - [ ] **Action**: In the Portainer Stack configuration, upload or define the variables from `stack.env`.
   - Important: Ensure `DOMAIN` is set correctly for WebAuthn/FIDO2 to function.
   - Temporary: Keep `SIGNUPS_ALLOWED=true` initially.
+- [ ] **Action (Admin Token)**: The Vaultwarden Admin Panel requires a secure hash, not plain text. To generate it, SSH into your NAS and run:
+  ```bash
+  docker run --rm -it vaultwarden/server vaultwarden hash
+  ```
+  Enter your desired admin password, copy the generated `$$argon2id$$...` string, and paste it as the `ADMIN_TOKEN` value.
 
 ### Deploy Stack
 - [ ] **Action**: Create a new stack named `vaultwarden-stack`.