Adapt.on('popup:opened') listener leak in NarrativeView.openPopup #345

Subject of the issue

Every call to openPopup() in NarrativeView.js registers a new anonymous Adapt.on('popup:opened', ...) listener that is never removed:

https://github.com/adaptlearning/adapt-contrib-narrative/blob/master/js/NarrativeView.js#L319-L322

Because it's bound with Adapt.on() directly (not this.listenTo), and a new closure is added on every popup open, listeners accumulate for the lifetime of the page. Each accumulated handler also fires for any popup opened anywhere in the course (not just this narrative's own), so currentItem.toggleVisited(true) runs for unrelated popups too.

Your environment

• Adapt Framework v6 / adapt-contrib-narrative 7.13.1
• Any browser
• N/A (logic bug, not device-specific)

Steps to reproduce

1. Add a narrative component with items that have a title or strapline set (so their popup can be opened).
2. Open and close a narrative item's popup several times.
3. Inspect Adapt._events['popup:opened'] in the console — its length grows by one on every open and is never reduced.

Expected behaviour

Only one popup:opened binding should exist per narrative view instance, cleaned up with the view, and it should only react to the popup that narrative instance itself opened.

Actual behaviour

Listeners accumulate indefinitely, and any popup opened elsewhere in the course incorrectly marks the narrative's current item as visited.