v0.5.1 — telegram-dev

• Why 0.5.1 and not 0.5.0: a v0.5.0 tag was pushed by mistake on the
  previous main commit, before this change had merged. Its release run was
  cancelled before anything was published (npm stayed at 0.4.0, no GitHub
  release), and the repository rules keep tags, so that tag stays and names no
  release. Nothing was ever published as 0.5.0.

• telegram-bots: new reference references/high-load.md. One slow update
  must not hold every chat. Telegraf 4.16.3 awaits Promise.all over the whole
  batch before the next getUpdates and races each handler against a 90 s
  handlerTimeout (read in its source on 2026-10-23), so one handler waiting on a
  slow Telegram stops the bot for everyone. The page covers a dispatcher behind
  bot.handleUpdate (a queue per chat, a ceiling across chats, a per-chat cap,
  payments outside the ceiling), guards that must measure from arrival once work
  is queued, why a screen must not be superseded at queue time, timeouts that
  free the caller rather than the work, a shutdown that stops the poll first and
  refuses to restart it, and the measurements and non-flapping alarms that show
  the problem before a user does.

• New fixture fixtures/update_pump.py. A discrete-event simulation on a
  virtual clock with nine rules; --self-test removes each and watches its
  invariant fail. Run by npm test.

• Lessons come from the verification rounds of a production bot's dispatcher
  (2026-10-23/24); no project is named.