Rush 0.1.0 alpha 16 — the early shape of home

Where Rush home took shape. Alpha 16 is the build where the home screen, the agent cards, and the input bar all landed in the layout we still ship today — agents as the first-class entity, the input bar as the gravity well at the bottom, context chips and the @ picker as the universal primitive.

First systematic QA. This was the first alpha to run through the fresh-install gate — wipe the machine, install from a signed DMG, screenshot every state, archive the result. The QA discipline from this point forward catches the install-time regressions that don't show up on dev machines.