Timeless Question Autocomplete

Fixes her reply page being left open after a correct answer.

Evelyna acknowledges a correct answer with a gossip page that has no options at all. The addon only handled the one-option case, so it did nothing and the window stayed open until dismissed by hand.

It now closes that page, with two guards: only within 15 seconds of having answered, so idly talking to her still opens her dialogue normally, and never while a quest is on offer, so a player who hands the quest in by hand does not get the window snatched away.

Also adds a headless test harness that runs the shipped files in a real Lua VM against a mock client, covering the whole sequence — accept, answer, dismiss, hand in — plus both guards and the wrong-answer-then-retry path. Both bugs found in this addon so far were flow bugs no linter would catch.