Adds 6 steps (482-487) for architect/worker dispatch: step spec expander,
convention extractor+validator, prior-step context injector, worker
dispatch protocol, test plan generator with 9-type taxonomy, and
integration proof. Replaces "12 tests per step" invariant with
complexity-driven test planning.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>