mk-pnpm-cli restored workspace lacks @typescript/typescript-linux-x64 (TS7 tsc fails in sandbox builds)

[schickling-assistant]

Context

Building blocky-scg-worker from dotfiles (attr blocky-scg-worker, depsBuilds FOD refreshed post pnpm-12.4.1 float) fails inside the sandbox after workspace restore:

file:///build/workspace/node_modules/.pnpm/typescript@7.0.2/node_modules/typescript/lib/getExePath.js:53
Error: Unable to resolve @typescript/typescript-linux-x64. Either your platform is unsupported, or you are missing the package on disk.
    at getExePath (typescript/lib/getExePath.js:53:19)
    at tsc (typescript/lib/tsc.js:6:13)

TypeScript 7 resolves its native binary from the optional platform package @typescript/typescript-linux-x64; the restored workspace contains typescript@7.0.2 but not the platform package, so any sandboxed build step that shells out to tsc fails.

genie/native-dependency-policy.ts already lists '@typescript/typescript': { _tag: 'pure-package-artifact' }, so the family is known — the dependency-materialization profile / restore path for install roots that transitively need tsc appears to miss it.

Impact

• dotfiles check:blocky-scg-worker-artifact (build layer; the pnpm-deps FOD fetch layer is fixed separately)
• dotfiles check:scg-deploy-preprod-harness (its scg-deploy/test-script closure builds blocky-scg-worker)

Darwin builds will need @typescript/typescript-darwin-arm64 symmetric handling.

Repro

nix build .#checks.x86_64-linux.blocky-scg-worker-artifact-check -L
# or directly: nix build /nix/store/8n3s4yn00ncpakyp9sjqcss2j19l2ach-blocky-scg-worker-artifact-check.drv

Posted on behalf of @schickling

field	value
agent_identity	dev3.direct.omp.fds258a8
session	unknown
agent_persona	generalist
agent_supervisor	unavailable
agent_tool	OMP
agent_tool_version	18.1.14
agent_runtime	OMP 18.1.14
agent_model	openai-codex/gpt-5.6-sol
worktree	2026-09-12-fix-checks/2026-09-12-fix-checks
tooling_profile	dotfiles@44ddd8a