fix(newsfeed): fix full article view and add framing check

[KristjanESPERANTO]

I was playing around with the newsfeed notification system (ARTICLE_MORE_DETAILS, ARTICLE_TOGGLE_FULL, …) and discovered some issues with the full article view:

The iframe was loading the CORS proxy URL instead of the actual article URL, which could cause blank screens depending on the feed. Also, many news sites block iframes entirely (X-Frame-Options: DENY) and the user got no feedback at all — just an empty page. On top of that, scrolling used window.scrollTo() which moved the entire MagicMirror page instead of just the article.

This PR cleans that up:

• Use the raw article URL for the iframe (CORS proxy is only needed for server-side feed fetching)
• Check X-Frame-Options / Content-Security-Policy headers server-side before showing the iframe — if the site blocks it, show a brief "Article cannot be displayed here." message and return to normal view
• Show the iframe as a fixed full-screen overlay so other modules aren't affected, scroll via container.scrollTop
• Keep the progressive disclosure behavior for ARTICLE_MORE_DETAILS (title → description → iframe → scroll)
• Delete fullarticle.njk, replace with getDom() override
• Fix ARTICLE_INFO_RESPONSE returning proxy URL instead of real URL
• A few smaller fixes (negative scroll, null guard)
• Add NEWSFEED_ARTICLE_UNAVAILABLE translation to all 47 language files
• Add e2e tests for the notification handlers (ARTICLE_NEXT, ARTICLE_PREVIOUS, ARTICLE_INFO_REQUEST, ARTICLE_LESS_DETAILS)

What this means for users

• The full article view now works reliably across different feeds
• If a news site blocks iframes, the user sees a brief message instead of a blank screen
• Additional e2e tests make the module more robust and less likely to break silently in future MagicMirror versions

[sdetweil]

Nice work.
one investigative question

why not use the jdk file?

Supposedly it’s as functional as direct dom.
just a question. I have used similar functionality via Angular

[KristjanESPERANTO]

why not use the jdk file?

The full article view now has an async step (server checks headers before showing the iframe), so the DOM needs to react to a callback. With a template you'd render it and then immediately manipulate the result via querySelector anyway — at that point the template doesn't add much. The old one was only 3 lines, so moving it into getDom() felt simpler.

[rejas]

No complains from my side other then the question if the translations were done with AI?

[KristjanESPERANTO]

if the translations were done with AI?

Yes, I used Gemini for the translation. I will try to include this information in future PR texts.