docs(agents): answer challenges before continuing work

A user question or challenge is the current task; resolve it before doing unrelated work.

Assisted-by: DeepSeek Harness (deepseek-flash)

agents/global-rules.md

@@ -218,6 +218,8 @@ For an impactful change, follow these steps in order, scaled to its risk:
 - Answer before acting. When the user asks, the answer or recommendation comes before new tool work;
   when the answer needs investigation, say in one line what you will check, then answer rather than
   reporting only the investigation.
+- When the user questions or challenges prior work, stop and answer that concern first. Do not
+  continue with other tool work or bury the answer under new changes.
 - Keep every turn steerable. Before work that will keep the user waiting, state the interpreted
   target, action, expected duration (when knowable), and artifact in one line, run it as a
   background job, and end the turn with its status and next step; let the job's completion event