Custom channel reordering & ability to hide default channels

1. Reorder custom channels — Let users drag/arrange their custom channels in whatever order they want. As people add more channels and make changes, they need a way to organize them intentionally rather than being stuck with creation order.

2. Hide/disable default channels — Give paid subscribers the option to hide the built-in default channels so they can have a view that shows only their custom channels. Not deleting them permanently, just toggling visibility.