Proving the media-on-a-prim ↔ in-world bridge. Not the product — a wiring test.
This is the make-or-break question for an in-world editor. If typing feels bad here, the whole product premise needs rethinking.
Uses fetch(..., {mode:'no-cors'}) — the request reaches LSL but the reply is opaque to JS. Watch your local chat for the coordinator announcing receipt. That's the round-trip proof.