Testing multi-agent crews: forcing split-brain, goal drift, and context drift to happen in CI

Coordination failures don't show up in a test suite because the test run happens to schedule agents politely. Split-brain needs a specific interleaving, goal drift needs a specific chain of lossy handoffs, and context drift needs a correction that lands mid-run. All three can be forced deterministically: a scripted scheduler that controls who reads and writes when, a handoff chain with an assertion on the constraint ledger instead of on the output, and a mid-run policy change with a stale-holder check. Concrete harness code, what each test asserts, and why you should not assert on model output at all.