fix: expand configured service usernames

src/archive_clients/config.py

@@ -169,6 +169,8 @@ def _service(value: Any, name: str) -> ServiceConfig:
     username = value.get("username")
     if username is not None and (not isinstance(username, str) or not username):
         raise ConfigError(f"{name}.username must be a non-empty string")
+    if username is not None:
+        username = _expand(username)
     addresses = value.get("advertised_addresses", [])
     if not isinstance(addresses, list) or any(
         not isinstance(address, str) or not address for address in addresses