Non-TTY children spawned by the verification runner hung until the hard
timeout when Corepack prompted before fetching a pinned packageManager
version. Set COREPACK_ENABLE_DOWNLOAD_PROMPT=0 in the spawn env so the
fetch proceeds (or fails fast) without waiting on stdin.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Cleans up lint and type errors in the engine by removing unused imports from executor and merger, and replacing `any` types with proper type annotations in verification-utils.
Fusion-Task-Id: FN-3345
