retro-candidate: work order changed CI event triggers without deciding base-retarget routing, forcing needs:replan

Occurrence: https://github.com/mochan-tk/agentic-dev-kit-for-copilot/issues/138#issuecomment-5739633709

Task #138 ordered the code CI pull_request event set to be narrowed (AC2) while requiring that body-only edits at the same head never re-run code checks (AC6), but the work order did not decide how base-retarget edited events, which change the comparison target, should be routed. The supervisor stopped with needs:replan before dispatching a worker; the owner decided Option A (https://github.com/mochan-tk/agentic-dev-kit-for-copilot/issues/119#issuecomment-5739663111) and the requester amended the body (https://github.com/mochan-tk/agentic-dev-kit-for-copilot/issues/138#issuecomment-5739669303). The pause was correct, but the decision belonged in the work order: a Task that changes event triggers or comparison targets should state the boundary before dispatch.

This issue records the planning gap only (first occurrence); it does not authorize template or planner changes.

Read issue #138 and the linked comments, then review the Option A decision in issue #119. This issue is a retrospective record only: it does not request template, planner, or code changes. Done means preserving the documented planning gap and its resolution without implementing a change.