a single-page result (max_pages < 2) suppressed the navigation row by dropping the
whole view, which also discarded the consumer's custom per-page buttons. now: if the
page carries custom buttons, keep the view and rebuild with update_buttons(nav=False)
— nav items suppressed, custom buttons kept, and stop() NOT called so their callbacks
still fire. a page with no custom buttons keeps the original drop-the-view behavior.
verified by execution against real discord.py: single page + custom button -> start()
-> callback FIRES on click (view kept, stop() not called); negative control on the old
code drops the button entirely; the no-button single-page case is unregressed.
Signed-off-by: disqualifier <dev@disqualifier.me>
empty pages gave max_pages=0; get_page(0)/start() then IndexError'd on self.pages[0].
guard in __init__ with a clear ValueError instead of a deferred crash at render.
verified: ButtonPaginator([]) -> ValueError; non-empty and single-page intact.
Signed-off-by: disqualifier <dev@disqualifier.me>