New free tests from the ship coverage audit: test/gstack-render-cli.test.ts
(argv guards, --help, output contract with a fake daemon, failure and
serve-root paths, no-browser case, prompt exit), test/setup-needs-build.test.ts
(every binary and source set flips NEEDS_BUILD, Windows suffixes),
make-pdf/test/cli-exit-codes.test.ts and setup-smoke.test.ts (error to exit
code mapping, runSetup stages, renderPdf's engine), and prose-span cases for
extractBrowseCommands in test/skill-parser.test.ts.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
