fix(docs-eval): tolerate nested artifact layout in CI executor

[alexluong]

The docs-agent-eval job (run 29858282052) failed with no .ts file found even though both scenarios passed scoring: the scenario-02 agent laid out its quickstart as a typescript/ subproject, and execute-ci-artifacts.sh only globs the run-dir root. Agent file layout is nondeterministic, so root-only discovery flakes.

pick_sh/pick_ts now fall back to a recursive search (node_modules pruned, .d.ts skipped, quickstart names preferred, sorted so the pick is deterministic), and install/execute run from the picked file's directory so a nested package.json and .env stash apply. The smoke test writes its TS project under typescript/ to keep the nested path covered, and the agent prompt template now tells quick-path runs to write files directly in the working directory — that lowers drift; the executor change is what removes the failure mode.

Verified by replaying the failed run's downloaded artifact through the executor: unpatched reproduces no .ts file found; patched picks typescript/outpost-quickstart.ts and proceeds to execution.

🤖 Generated with Claude Code