Single house style for every hand-rolled usage line: 'Usage: aura <verb> ...'
(clap's capital prefix + program name), 10 literal edits + the one
casing-sensitive test pin in lockstep. Refusal diagnostics, the conforming
run_args_from site, clap output, and the fieldtests corpus stay byte-identical.
Grounding-check PASS is the autonomous signature; scope-fork decisions are
recorded on the issue.
refs #179
