v0.13.3

Changed

• README install section split into "Try without installing" /
  "Install for daily use", each showing both npm and bun.
  The previous structure mixed an npx agenthud install hint with
  bare agenthud … Quickstart commands — copy-paste failed for
  anyone who took the trial path. Two clearly-labeled H2 sections
  now exist side-by-side; the Quickstart still targets the
  daily-use form, and bun users are first-class instead of
  "check the docs". Doc-only; no behavior changes.