Add LimeApp user guide

[luandro]

This picks up #173 and ports the LimeApp 1.4 docs from AlterMundi into our English guide.

What I added:

• 14 new pages under docs/guide/limeapp/: overview, access, menu tour, status, alignment, map, diagnostics, notes, node config, network config, firmware, visit neighbor node, remote support, and the aligning-antennas tutorial.
• 66 screenshots self-hosted under docs/public/guide/limeapp/images/, so the guide works offline and we don't hotlink.
• A new "Using LimeApp" entry in the sidebar (Usage Guide), collapsed by default.
• A short pointer from docs/guide/connecting.md.

A few notes:

• Translated from the Spanish original, with the screenshots kept as-is. A ::: tip on the index page explains which UI labels map between the two.
• Attribution to AlterMundi and the CC BY-SA 4.0 licence is on every page.
• The PDF booklet and forum links still point to the original Spanish resources.
• The full PDF booklet and the LibreRouter forum are kept as external links.

Built locally with pnpm run build and walked through on the dev server — all pages and images load fine.

Happy to split this up or tweak the wording if you'd prefer smaller PRs or a different sidebar structure.

[a-gave]

Great! Thanks a lot!

Some minor notes:

• All the outline: deep can be removed since it is the default in docs/.vitepress/config.mts
• I would rename the paths in docs/guide and docs/public/guide from limeapp to lime-app which is the same name as the git project
• I would add all lime-app's menu items inside a nested menu under 'A tour of the menu': so it reflects totally the lime-app's menu and seems easier to understand at first glance, and it becomes clear that "aligning antennas" is a separate section of the guide from the menu items

Adding here a note to myself, that is to add a section like 'additional package selection' that mentions that to fully utilize all menu items in the lime-app one should have installed:

• shared-state-async and shared-state-bat_hosts to have 'Visit neighboring node' working
• pirania for 'Access vouchers'
• soportoremoto for the remote-support
  With the profile-libremesh-suggested-packages-tiny which use 'shared-state' and not 'shared-state-async' the tabs which works are 'status', 'alignment' and 'metrics'