docs: rewrite README with English on top, expanded usage, and badges

- English section moved to the top, original Japanese content kept
  below it in full (translated/updated to match, nothing removed).
- Removed the pip/PyPI and apt/bloom publishing walkthroughs from the
  README -- not useful to someone just using the package; moved to
  .docs/PUBLISHING.md for maintainers instead (see that PR).
- Expanded the usage section: full colcon lbuild/lb option reference
  (--event-handlers, --continue-on-error, --parallel-workers/-j/--jobs),
  colcon lclean/lc options, how to try the bundled demo workspace, how
  to use the live_status event handler without the verbs, locale
  detection for this package's own help text, and non-TTY behavior.
- Added CI / PyPI version / Python versions / license badges at the top.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: RyodoTanaka