Queries the terminal's actual background color via OSC 11. Resolves
null immediately, with no query attempted, when stdin/stdout aren't a
TTY (piped/scripted/CI usage) -- and resolves null after a short
timeout if the terminal never responds (unsupported terminal, or a
multiplexer/SSH chain that swallows the query).
Queries the terminal's actual background color via OSC 11. Resolves
nullimmediately, with no query attempted, when stdin/stdout aren't a TTY (piped/scripted/CI usage) -- and resolvesnullafter a short timeout if the terminal never responds (unsupported terminal, or a multiplexer/SSH chain that swallows the query).