style(panel): give the navigation column's mark the column's full width

The mark kept the 110px it had as part of the bar, which was all there was
room for in a row; in a column it ended halfway across, sharing an edge with
nothing below it. At the column's width its edges line up with the page
entries, and the SVG's own inset puts the drawn mark on the entries' icons.
The width/height attributes carry the file's real proportions so the column
still reserves the right height before the SVG loads.

Where the column lies back down into a bar, the mark returns to the compact
size: at full width it would take a row to itself above the entries.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

internal/web/templates/layout.html

@@ -55,7 +55,7 @@
        the column: the mark, the panel's pages, the current page's own sections,
        and the session last. The mark goes to /status, the page the panel opens
        on — named outright rather than as "/", which is only a redirect to it. */}}
-  <a class="brand" href="/status"><img src="/static/logo-compact.svg" width="110" height="50" alt="SelfPost"></a>
+  <a class="brand" href="/status"><img src="/static/logo-compact.svg" width="220" height="100" alt="SelfPost"></a>
   <div class="links">
     {{if eq .Active "status"}}<span aria-current="page">{{template "icon-status"}}Status</span>{{else}}<a href="/status">{{template "icon-status"}}Status</a>{{end}}
     {{if eq .Active "domains"}}<span aria-current="page">{{template "icon-domains"}}Domains</span>{{else}}<a href="/domains">{{template "icon-domains"}}Domains</a>{{end}}