agent/pre-step already runs before step/start, and tool resolution and prompt
assembly now follow step/start, so plan-mode can keep committing pending
selections after downstream pre-step listeners accept the step. Tool
conditions and plan guidance still read the committed state, and a rejected
proposal keeps the selection pending as on master. No agent/model listener
depends on plan mode, so the separate serial event had no consumer left.
The loop now claims input, runs agent/model, and then agent/pre-step. The
agent/model order test replaces the boundary tests; plan-mode tests cover
the rejected-proposal case again. Docs, the Agent Note, the upgrade guide,
and generated catalogs follow.