nx_domseed_test.nx

nx_domseed_test.nx -- controlled proof that the sniff now seeds the page HTML as the DOM: an element carries a data-* stream URL; inline JS reads it via document.getElementById(...).getAttribute(...) and fetch()es it. If the DOM seed works, getElementById resolves the element, getAttribute returns the m3u8, fetch registers it, and the harvest surfaces ROUTE=hls. If the DOM is NOT seeded, getElementById returns null -> TypeError -> ROUTE=none.