Bevy origin picker: title-screen parity (chargen crit 3) master
The Bevy title screen now mirrors the terminal origin picker: Game gains selected_origin (default Pilot) and Game::start_run (rebuilds the sim with the chosen origin before Playing); title input cycles origins with arrows/h-l and any other key begins; the title text shows the origin name, lean, and built-to line. Bevy previously had no way to select an origin at all. Completes chargen criterion 3's picker in both frontends (the axis-on-core-card readout already landed in both). Only the objective axis in the same picker remains, a no-op today while Persist is the only objective. Defense: Pilot-safe and additive — default selection is Pilot and start_run only rebuilds on a change, so no-choice play is byte-identical. Pinned by the Bevy title_picker_start_applies_the_selected_origin; bevy tests pass, fmt/docs gate green. Both frontends read the same Sim::origin and share the picker shape, so terminal/Bevy stay in parity.