Universal workspace chrome substrate — the orchestrator and its sub-classes that every WorkspaceShell-derived AppModule shares. Born from a refactor: prior to this module, the entire workspace boot sequence (WorkspaceLayout mount, MTP wiring, picker plumbing, persistence attach, identity resolution, event-log + replay, checkpoint store, Web Lock + read-only fence) lived as ~2,100 lines of JS-as-Java-string-literals inside per-workspace chrome ...