* fix(single-instance): propagate D-Bus setup and handoff errors
* chore: satisfy release metadata and test header checks
* fix(single-instance): launch normally without a D-Bus session bus
Log a warning instead of failing setup when the session bus is unreachable, and add context to handoff errors.
* ci: run the single-instance D-Bus test under dbus-run-session
Run it in test-rust on Linux and keep it out of the updater integration job, which has no session bus.
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Co-authored-by: Lucas Nogueira <lucas@tauri.app>
