Docs: caught up with v0.13.0 to v0.19.0

The documentation had kept up feature page by feature page and nowhere
else. Now also:

- the home page's App cards (notes of any size, pictures, sharing) and its
  note (the Shell, the VPN, the screenshot key);
- the guide: VPN in the Status Bar and in Settings, the three keys that work
  everywhere, screenshots of the Shell, a picture, sharing, the VPN page and
  the help panel;
- three how-tos: move files with your phone, set up the VPN, take a
  screenshot; where the files are and what things cost in memory;
- the FAQ: screenshots, and what listens on the network;
- the README's opening: what the firmware does today;
- the glossary: Tunnel, Sharing, Screenshot;
- every milestone's status line, with the version each thing shipped in.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

site/content/dev/milestones/r1.md

@@ -8,7 +8,7 @@ docs = true
 source = "docs/milestones/R1.md"
 tag = "R1"
 +++
-**Status:** in progress. CI and signed releases on Gitea (issue #5) are in place since 2026-10-06: every tag from v0.1.0 to v0.10.0 has its release. Updates from Gitea (issue #6) is built and checked on the device, on branch `gitea-updates`, not merged yet. The Issues App (#4) comes after.
+**Status:** in progress. Shipped: CI and signed releases on Gitea (issue #5), a release for every tag; updates from Gitea (#6, **v0.11.0**); one firmware with the Debug Console in it (#68, **v0.12.0**); CI in about a minute (#74, **v0.13.0**). Not started: the Issues App (#4), automatic installs (#52), release channels (#53), resuming a download (#54).
 
 **Goal:** a tag is a release, built the same way every time and published where a device can find it.