The 420px "compact topbar" breakpoint left a gap: at 421-440px the demo-guide trigger,
badge, operator block and logout button together overflowed the viewport (introduced by
this session's language-switcher addition). Widen the breakpoint to 440px.
Adds a dedicated Playwright spec asserting no horizontal overflow across the brief's full
7-breakpoint matrix (1440x1000 down to 360x800) in all three supported languages.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
