Feature: Support windowed projectors

[kanjieater]

Currently, there is no way to open a windowed projector using obs-cmd. All projectors are forced into fullscreen mode.

According to the OBS WebSocket v5 specification, opening a windowed projector requires the monitorIndex field to be completely omitted from the payload. Because obs-cmd always sends a monitor index (defaulting to 0 if not specified), OBS always opens the projector in fullscreen.

Could we get a way to omit the monitor index or a flag to spawn windowed projectors?

[grigio]

Honestly it's a feature i don't use, but I'd consider a PR.