Nutshell section should list user benefits, not product features

At https://get.kiwix.org/en/solutions/applications/kiwix-reader/ and looking at the nutshell section, there is a mix of features and benefits. Only the latter are relevant from a user point of view ("People don't buy features, they buy benefits")

* Offline & Ad-free: The first sentence ("browser-like designed to open ZIM files") is a technical definition and should be cut. Explaining how the magic works kills the magic. Ergo, "Access knowledge anywhere, without internet access. No ads, no tracking."

* Multi-platform: This is a spec list. The benefit is "Use the same library on your phone, tablet, laptop or local network". One sentence to replace the whole platform enumeration.
* Your pocket library: The benefit is buried under jargon ("ZIM files," "local hotspot," "Kiwix Hotspot"). "Carry the entirety of Wikipedia, and more, in your pocket and share knowledge with everyone around you." Move it up to position 1
* Free & Open source: FOSS is an ideology that to most people sounds like "Cumbersome UI/UX". We also are not part of the Open-Source Initiative so I'm a little worried by the use of their logo. The real benefit is "No cost, no lock-in, auditable by anyone for increased security". The GitHub link belongs in a footer, definitely not as oversized link button. Put this as second-to-last, not on the first line.
* Trusted worldwide: downloads are social proof not benefits so keep in last position. Rephrase to "Trusted by millions" and make proof shorter/sharper "Kiwix has been downloaded millions of times and is used by schools, NGOs, libraries, governments, and individuals around the world."

Discard:
* Wikipedia is brand history, not a benefit. Merged with the pocket library benefit.

If removing the Wikipedia feature brings the number down to five and causes issues because of the odd number of benefits, then remove the FOSS thing which is a double-edged statement (and should be a given), much like stating that food is vegan actually [_lowers_ takeup](https://www.media.mit.edu/projects/v-labels/overview/). Or add an "Access for the long term" item with a description that reads "Build collections that remain available for years, without subscriptions or external services."

Open the linked Kiwix Reader page and locate the nutshell section. Replace the feature-focused copy with the specified user benefits, reorder the items, and verify the final number and wording on the rendered page.

Written by the indexing model from the issue text.