Run every ordered group through the same rolling pool: an exclusive call is a
pool of one (a barrier), dropping the separate runExclusive path and the
redundant post-grouping executionMode re-query. Behavior is unchanged — the
parallel-tool-calls snapshot and the full scheduler unit suite (barriers, cap,
abort, model-order results) stay green.
Add AgentLoop.Config.maxParallelToolCalls as a factory-wide default applied to
every agent create/createAgent/resume mints (per-agent option overrides it),
forwarded through agent-core so it reaches front doors that expose no cap field
of their own. Trim the isConcurrencySafe JSDoc to the local contract and link
the parallel-tool-call RFC for the full rationale; document the field on the
canonical core-data-structures page.
