* test(e2e): share the CLI version rule, env lockdown and rate limiter in tests/e2e/cli_harness
Moves the npm release rule (now taking the package name), the env allowlist plus fresh HOME, and the per-upstream rate limiter out of claude_code so the Codex suite can reuse them. Claude Code behavior is unchanged, its CI, cron and Dockerfile paths now call the shared resolver with @anthropic-ai/claude-code
* test(e2e): freeze the packument map and note the rate limiter self-test
* test(e2e): race real processes on one rate limiter bucket so a missing lock fails
Eight spawned processes start together and drain a bucket that never refills. With the flock they get exactly its burst between them, without it every attempt is granted
* test(e2e): keep the old Claude Code version resolver path for the Buildkite runner images
The runner Dockerfiles still run tests/e2e/claude_code/pr_gate_version_resolver.py and silently install @latest when it is missing, which drops the three day review window. The old path now forwards to cli_harness/npm_version_resolver.py