Idle cost depends on which surfaces are mounted, so the profiler needs to
reach those states without a human driving the UI.
`--panel <mode>` opens the context panel by seeding the persisted store the
app reads on boot, using the same tab identity rules as `useUIStore`.
`--then-tab <name>` navigates through the router after settling, which leaves
already-mounted surfaces mounted and measures what a screen keeps doing once
the user has moved on. Both drive real application state instead of
synthesising clicks, so the recorded window stays free of input-driven work.