The post-/runda DA pass on 4cd574b found the persist-on-unload wiring
(quit + project switch calling Database::set_mode) had no integration
test — only the db-level set_mode behaviour was covered, not that the
runtime actually invokes it on unload.
Add runtime::switch_persists_the_outgoing_projects_mode, driving the
real handle_project_switch end-to-end and asserting the outgoing
project's project.yaml recorded the mode it was left in. Red-first
verified: with the set_mode call disabled it fails (None vs
Some(Advanced)). The quit unload site shares the same set_mode call;
Action::Quit emission is already covered in app tests.
Updates ADR-0015 Amendment 1 coverage note.
claude@clouddev1
516848ff63