Composable pre-deploy gate that scans built JS chunks for substring overview

Composable pre-deploy gate that scans built JS chunks for substring markers listed in a project-local `forbidden-markers.txt`. Designed for injection into deploy and quality-gate processes to enforce structural guarantees against the revival of saga-era / obsolete code paths after a refactor. The module provides three surfaces: - `parseForbiddenMarkers` — synchronous parser (blank lines + `#` comments stripped) - `scanForbiddenMarkers` — async scanner returning structured `{ ok, hits, reason }` - `checkForbiddenMarkersTask` — babysitter `defineTask` wrapper for harness-driven use Origin: ported from the cookbook prototype `scripts/check-no-forbidden.mjs`, which proved the pattern across the VI-restart / iOS-Safari saga (2026-05). Upstreamed for the babysitter process library per issue #477.