* test(desktop): exercise packaged app startup
The previous smoke exited before IPC, window creation, and preload execution, so a broken packaged preload could still pass. Launch the normal app and observe its renderer bridge and managed daemon through CDP instead.
* test(desktop): preserve Linux sandbox in smoke
Configure the unpacked artifact's chrome-sandbox helper with the permissions Electron requires, while keeping sandboxing enabled so preload failures remain observable. Bound startup probes and include process logs in daemon timeout failures.
* ci(desktop): keep packaged smoke on releases
Remove the temporary pull-request artifact build after it validated the Linux launch path. Keep the real packaged smoke in the native desktop release matrix.
* ci(desktop): gate packaged smoke by changes
Run the Linux real-artifact smoke in pull-request CI when packages/desktop changes, while leaving the regular desktop unit-test matrix unconditional.
