Send one-off browser actions with _ExecuteCommand

GlobeControl gets FlyTo, SelectQuake, ClearSelection, Follow and
ToggleSpin, and CommandPalette.Open, each calling the public JS method of
the same name through _ExecuteCommand. This replaces the command queue
that was serialized with sequence numbers, so Serialize now carries only
persistent state. A fly-to requested before the globe finishes loading is
kept and applied once it's ready.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
