* fix: reconcile planner action contract
The deep_work_rules workflow block was stronger than the planner agent contract: it required verbatim context copies and self-sufficient action text, so planners were incentivized to inline implementation code. Bound action content to directive prose with concrete identifiers, allow behavior/test acceptance criteria, and pin the cross-file contract with a regression test. Closes#3320.
* chore: add changeset for planner contract fix