Vug::FetchDecision

A loop-control decision made by the fetch loop after each round-trip.

Replaces the {LoopAction, String?, URI?} 3-tuple that the loop used to return from its dispatch helpers. The tuple was easy to misorder, and the third element silently flipped between current_uri (pass-through) and nil (force re-parse) depending on the action — a hidden side-channel the caller had to know about.

reparse: true is set when the loop should drop its cached LoopState#current_uri so the next iteration re-parses from the (possibly new) state.current_url. The other fields carry the action and the optional next URL exactly as before.