throughline

Throughline plugin: a PRD/TDD/ADR design-doc pipeline with phase-gate PRs, layered as a thin governance overlay on top of the official superpowers/pr-review-toolkit plugins (it owns governance; they own discovery + engineering). /prd-author requires an observable acceptance criterion per new requirement. /tdd-author decides how many TDDs a PRD change needs (git-diff + coverage), recommends ADR actions, requires an alternatives analysis for every new dependency, requires a verification plan (observable surface → observation point(s) → expected observations) per TDD, reads BLOCKERS.md so implementation-time design blockers feed back into design, self-reviews, then runs an independent design-critique gate (different model, fresh context) before the design PR. /implement builds every TDD merged to the integration branch unattended in detached processes on the latest top-tier model but does not trust self-reported success: the flip to implemented is gated on failing-test-first discipline, a mechanical ci-checks gate (tests+typecheck+lint — CI's job), a runtime-verify gate that drives the built artifact at its observable surface (PASS/FAIL/BLOCKED/SKIP kept distinct; mechanism delegated, no harness vendored — ADR 0004), and an independent review on a DIFFERENT model (the prior generation's top tier) for reviewer diversity — one stacked PR per TDD, downstream halt-on-failure, never merges. Includes a toolchain bootstrap skill and a format+lint hook for JS/TS, Python, Rust, and Go.