[receive] Universe discovery has_all_pages() can panic

[bruingineer]

pub fn has_all_pages(&mut self) -> bool {
    self.pages.sort_by(|a, b| a.page.cmp(&b.page));
    for i in 0..(self.last_page + 1) {
        if self.pages[i as usize].page != i {
            return false;
        }
    }
    true
}

This indexes self.pages[i] without checking length.

If

• receive page 1 before page 0, or
• miss any page, or
• receive duplicates and still don’t have a full contiguous set,

then

• self.pages.len() can be < last_page+1 and this will panic.

In handle_universe_discovery_packet(), if the first packet seen from a source is page > 0, it still creates a partially discovered source with that single page. Later, has_all_pages() can be called while still missing page 0, and will panic.

Fix: check self.pages.len() >= (self.last_page as usize + 1) before indexing, or rewrite to a set/bitmask presence check.