feat(acp): emit session plan from todo updates - #40746

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The following comment was made by an LLM, it may be inaccurate:

I found a potentially related PR:

Related PR:

• feat(acp): emit plan session updates from todowrite tool calls #31834 - feat(acp): emit plan session updates from todowrite tool calls

  • feat(acp): emit plan session updates from todowrite tool calls #31834

  Why it's related: This PR also addresses emitting session plan updates from ACP, but specifically from todowrite tool calls rather than todo updates. The current PR (40746) extends plan emission to the todo.updated stream. These appear to be complementary efforts on the same feature area.

All other results were either the current PR (40746) itself or unrelated changes.

Closing as a duplicate of #31834 — it implements the same todo.updated → plan mapping and is further along (fingerprint dedup, richer tests). I'll help move #31834 forward instead of fragmenting the effort.