chore(release): prep v0.1.16 — say plainly which servers Tane talks to

The store listing claimed "No account, no server, no trackers" while the
app was dialling four relays at launch. The app side is fixed; this is
the half a reader sees.

- Store description, both locales: the false line is gone, and a new
  "Sharing needs the internet" block names relay.comunes.org (ours),
  nos.lol, relay.damus.io and relay.primal.net, says when Tane talks to
  them, what they can see (a key and an IP — no name, no account), and
  where to switch any or all of them off, or point Tane at your own.
  Deliberately plain: no protocol names, no jargon. The audience is
  gardeners; the technical detail belongs in the F-Droid thread.
- The same correction on the landing page (feature card, FAQ, status).
- 0.1.16+18, so the F-Droid recipe's versionCodes become 181/182/183.
  F-Droid reads fastlane metadata from the checkout of the newest built
  version, so the description only reaches it via a new release.

The recipe mirror's `commit:` still points at v0.1.15 — it needs a hash
that does not exist yet, and is synced here and in the fdroiddata fork
once v0.1.16 is tagged.

apps/app_seeds/fastlane/metadata/android/en-US/changelogs/18.txt

@@ -0,0 +1 @@
+Tane now stays completely offline until you join the sharing part — it no longer contacts any server on its own. The store description finally says which community servers it talks to, what they can see, and how to change them or switch them all off.