[dashboards] open-brain-dashboard-next: fix Sign Out button hidden behind iOS Safari URL bar

[tswicegood]

Contribution Type

• Dashboard (/dashboards)

What does this do?

One-character CSS fix in components/Sidebar.tsx: h-screen → h-dvh.

The sidebar uses h-screen (height: 100vh), which on iOS Safari is the largest viewport — the height when the URL bar is collapsed. While the URL bar is visible, the actual visible area is shorter, so the bottom of the sidebar — including the Sign Out button — renders below the fold and is effectively unreachable until you scroll-trigger the URL bar to collapse. On a fresh page load you can't sign out.

h-dvh (height: 100dvh, dynamic viewport height) makes the sidebar bound itself to the currently visible viewport, so the Sign Out button stays in view regardless of browser chrome state. Tailwind v4 supports the h-dvh utility natively — no config changes needed, no other code touched.

Repro / verification

• Before: open the dashboard on an iPhone in Safari with the URL bar visible — open the sidebar — the bottom (RestrictedToggle + Sign Out) is below the fold.
• After: same conditions — bottom of sidebar sits flush with the visible viewport — Sign Out reachable on first tap.

I tested this on my own deploy (Cloudflare Worker via OpenNext, current iOS Safari) before opening this PR.

Requirements

None — pure CSS class change. No new deps, no behavior change on desktop or other mobile browsers (h-dvh falls back gracefully where supported, and Mobile Safari has supported dvh since iOS 15.4).

Checklist

• I've read CONTRIBUTING.md
• No credentials, API keys, or secrets are included
• I tested this on my own Open Brain instance (live deploy, real iPhone, real URL bar)