pub fn emit(lvl: Level, msg: &str)Expand description
Emit msg at lvl through the active LogSink. Production
path: the default sink writes to stderr; the TUI’s
CapturedSink buffers for in-frame display; the level gate
suppresses below the configured threshold.
A thread-local capture (installed by [_test_capture_warns])
shadows the active sink and bypasses the level gate for the
calling thread — tests assert that a warn fires, not whether the
runtime gate happens to be open. Mirrors the existing always-fire
semantics of emit_error.