TestR578NothingTakesTheSettingsLockInsideASettingsCallback (internal/settings) derives from
source the *Settings methods that take s.mu, the callback runners among them, and per package
every helper that transitively reaches one; a call to any of those inside a func literal
passed to a runner (or a non-literal callback) fails with file:line. Decoy:
TestR578GateConvictsAHelperChain. REUSE.md lookalike row added.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS
