Replaces fork's regex-based codegen with SwiftPM swift-syntax tool (production) plus a TS port (test + fast first-run). Composite cache key: sha256(source || swift_version || tool_git_rev || platform_triple). Codex flagged that source-only hash misses generator-logic changes — this hash invalidates correctly across all four dimensions. 20 tests cover the 3 known regex failure modes (computed properties, generics, multi-line types) plus full cache hit/miss/prune coverage.
Authors ios-qa, ios-fix, ios-design-review, ios-clean, ios-sync as upstream gstack skills. Each follows the standard SKILL.md.tmpl pattern with preamble-tier:3 frontmatter. The fork at time-attack/gstack shipped these but as byte-identical .md/.tmpl pairs that wouldn't pass skill-docs.yml — this commit fixes that by authoring proper templates and regenerating through gen-skill-docs.
Garry Tan