ci(migrate): fixtures integrity check + pricing-cache staleness report

[herosjourney]

Summary

• Adds two zero-dependency TypeScript CI tools (Node 24 native type-stripping, same pattern as the existing validators), both wired into the lint aggregate so mise run build runs them:
  • mise run fixtures:check — structural integrity of the committed replay fixtures.
  • mise run pricing:staleness — reports pricing caches past their own declared freshness windows (warn-only in build; --strict for a scheduled gate).

Motivation: the fixture sets are the plugin's regression harness, and they rot in ways the build never saw — all three of these happened in practice: a capture manifest referencing files that were never committed (the repo-root .gitignore's build/ rule silently swallowed three canned .next manifests), a seed .phase-status.json lagging behind the phases the skill declares, and an asserter using Python-3.10-only syntax that crashes on 3.9. Separately, every pricing cache declares a freshness contract that nothing enforced — caches quietly went stale and every estimate degraded to fallback accuracy.

Changes

tools/fixtures-check.ts

Checks: every fixture JSON parses; every asserter ast.parses (no bytecode litter); every manifest captures[]/api[] entry with status ok resolves to a file on disk (failed/skipped may legitimately have none) and build.files[] exist; nothing under fixtures/ is gitignored; every seed phase list exactly matches the owning skill's declared _phase set. Takes an optional root argument to point at another worktree.

tools/pricing-staleness.ts

Reads each cache's own declared date and window (_meta.last_updated + staleness_days, or the markdown **Last updated:** header). Warn-only in build (a stale cache must not fail unrelated PRs); --strict exits 1 for a scheduled workflow. Currently reports 3 of 4 caches stale on main — the condition that degraded this week's estimate replays.

Supporting

• node-shims.d.ts extended (basename/relative/spawnSync) to keep the zero-dependency typing approach; tsconfig includes the new tools so lint:types covers them.

Relationship to other PRs

• chore(migrate): refresh pricing caches + weekly strict staleness workflow (stacked on #151) #155 (cache refresh + scheduled strict workflow) is stacked on this branch.
• Order-independent with the fixture-bearing PRs (feat(migrate): add vercel-to-aws migration assessment skill #141/feat(vercel-to-aws): add estimate phase + promote scaffold to full generate phase #144/feat(heroku-to-aws): live discovery via the authenticated Heroku CLI #148/feat(gcp-to-aws): live discovery via the authenticated gcloud CLI (stacked on #148) #149/feat(heroku-to-aws): live-captured prices for the Estimate baseline (stacked on #148) #150/feat(heroku-to-aws): post-Estimate what-if workshop checkpoint #152–154): the checker walks whatever exists; landing it first means they're guarded on merge.

Test plan

• mise run build green (both tasks run inside lint; lint:types type-checks the tools)
• fixtures:check PASS against all four in-flight fixture sets — after catching a real bug on feat(migrate): add vercel-to-aws migration assessment skill #141 (seed omitted the declared scaffold phase; fixed there as d11db7b)
• Negative tests: synthetic tree with broken JSON, broken asserter, missing ok-status capture, missing build.files entry, gitignored fixture, and an invalid seed — all 9 problems reported, exit 1
• pricing:staleness warn-mode exit 0; --strict exit 1 against main's stale caches