v0.4.7

Two more platforms a post can be read from without an account: Lobste.rs and Lemmy.

Added

• Lobste.rs. check --url https://lobste.rs/s/<id> reads a story — its title, its
  submitted address first and the links in its text — and /c/<id> or a #c_<id>
  fragment reads one comment, never the thread above it. Read from the .json twin
  of each page; no key, no account. A moderated comment is UNVERIFIED (blocked), a
  deleted one UNVERIFIED (unreachable), as spec §15 keeps them apart. An anchor
  pointing back at the story's own discussion page is not a source and is left out.
• Lemmy. check --url https://<instance>/post/<n> and /comment/<n> read from
  the /api/v3 every instance serves without a login. A post's submitted address
  comes first, then the markdown links in its body. removed (a moderator's doing)
  is UNVERIFIED (blocked); deleted is UNVERIFIED (unreachable). A private
  instance answers an anonymous reader with the same 400 as a missing post and
  not_logged_in in the body, so the body's token decides: not_logged_in is
  UNVERIFIED (blocked), couldnt_find_post is UNVERIFIED (unreachable), and a
  400 naming neither is UNVERIFIED (unavailable) — never a guess about the post.
  Lemmy is known by its host — the
  lemmy. prefix or one of lemm.ee, sh.itjust.works, beehaw.org,
  programming.dev, feddit.org — never by /post/<n> alone, which is how any
  blog addresses an article; a post on an instance outside that rule is read as a
  page, as before, and no /api/v3 request is ever sent to a host that did not say
  it is Lemmy.

Changed

• The "platform not read in this version" hint, the check --url help and the README
  table name all seven platforms.
• polite.ProviderError carries code: the one snake_case token a JSON error body's
  error field named, when it named one, and nothing else from the body. It is what
  lets the Lemmy reader tell the two facts above apart; no other caller reads it yet.