Implements the execa Agent Note's four sub-changes:
- execa (root devDep + loader-smoke dep) replaces the hand-rolled
spawn-collect-timeout choreography in loader-smoke, apps/cli and
cli-demo/acp-demo built-bin e2e, lsp-local and code-runtime-worker
built-lib e2e, the tui pty-harness outer collector, the jsonrpc
keyless smoke, and crash-recovery's child spawn. Genuinely custom
parts stay custom: cli-demo's interrupt-on-marker, jsonrpc's
line-predicate protocol driving, crash-recovery's SIGKILL-at-failpoint.
The two loader-smoke /* v8 ignore */ OS-error branches are gone.
- llm-mock-server CLI tokenizes via node:util parseArgs; numeric
coercion/bounds/cross-option constraints stay manual; pinned
error-message tests updated to the parseArgs texts.
- both loadRootEnv copies in apps/web/tests are deleted: the owning
vitest configs (web unconditionally, snapshot in record mode)
already load the repo-root .env before these files run.
- the four poll loops (acp-snapshot harness waits + crash-recovery
waitForFile) ride vi.waitFor with explicit {interval, timeout}.