Update documentation to treat the Tauri/HTML prototype as legacy and define Bigscreen as a native Qt/QML/C++ shell. Remove in-shell PIN/login as a target feature and clarify that account selection, sign-in, and session choice are handled by a controller-friendly OS login (SDDM) implemented under Desktop Mode. Add phased plan, build/run notes for Qt vs legacy Tauri prototype, and clarify session/login workflow and responsibilities across Bigscreen/, Desktop/, and the top-level README.
andrew
627c52a5b7