Redefine research-orchestrator, planning-orchestrator, and
architect-orchestrator from "background executor" to "inline
reference documentation". The agent files remain as the canonical
workflow descriptions, but the /ultra* commands now execute the
phases directly in the main command context instead of spawning
these agents as sub-agents.
The /ultra* command markdowns are now the de-facto orchestrators.
Splitting work into a separate sub-agent was incompatible with the
harness's treatment of the Agent tool (not exposed to sub-agents).
BREAKING CHANGE: These agents are no longer invoked. Any external
integration that spawned them directly should now invoke the
corresponding /ultra* command instead.
