Confirmed the theatre-mode preview dialog actually renders correctly
at phone widths (390x844) -- centers properly, backdrop and close
button both fine, nothing overflows. Added a `viewport` command to the
driver (defaults to mobile, since that's the step easy to skip) and a
CLAUDE.md rule to screenshot both breakpoints for future UI changes,
since the 860px sidebar/mobile-bar fork is a real, previously-hit
source of bugs here.
This sandbox ships with no Python/Node/Docker/browser and no sudo, so
the bulk of this is setup.sh: bootstrap Python via uv, then get
Playwright's Chromium (and tmux, also missing) working by extracting
their .deb dependencies non-root instead of apt-get install. driver.py
is a small Playwright REPL standing in for chromium-cli, which isn't
available here either.
Also carves out .claude/skills/ from the blanket .claude/ gitignore --
skills are shared project tooling, not personal/local state.