test(engine): no test asserts what content actually reaches the CLI invocation (staging review — PR #2018)

[rapiercraft-forgedock]

Problem

No test exercises the full runCommand → runCliBackend path asserting on the content delivered to the CLI. This is why BUG-1 (the dropped system prompt) was not caught by the new suite, despite the suite being otherwise strong.

A test asserting that the spawned argv contains the command spec would have failed on BUG-1.

Source: PR #2018 (staging → main deploy review) — finding BUG-3
Location: bin/tests/runner.test.mjs:1308
Confidence: POSSIBLE
Severity: LOW

Source Branch Context

Code branch: staging
Worktree base: origin/staging

When fixing: git worktree add ../fix-{slug} -b fix/{slug} origin/staging

Acceptance Criteria

• Finding validated: VALIDATED / FALSE_POSITIVE / INCONCLUSIVE
• If VALIDATED: fix implemented and tested on origin/staging
• Regression test added covering this path