25c767ddf2
PR 1.5 (commit 4168167) changed run_slot_injection's signature from
returning str to returning tuple[str, dict] so the scheduler can get
at the agentic message list for receipt persistence. The
test_run_slot_morning_runs_on_work_day mock was still returning the
old plain-string value, which unpacked to a ValueError at runtime.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>