The remote-config path passes a yaml.dump(...) string to
Gio.Application.run(), whose argv parameter is Optional[list[str]].
Pre-3.56 PyGObject tolerated a bare str; the marshaller refactor in
the 3.55 dev series (MR !487) tightened this, and 3.56 now raises
TypeError: Unable to marshal str as an array.
Wrap the YAML string in a 1-element list. The receiver in
solaar.ui._command_line already does yaml.safe_load("".join(args)) on
the argv, so a 1-element argv reconstructs the original YAML cleanly
under both old and new PyGObject.
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