fix: address PR review feedback on header CSS

- #header-status-host: flex: 0 0 0% -> flex: 0 1 auto so the teleported
  HeaderStatus (chapter title + % complete) is visible on all viewports,
  not just >=992px. Auto basis sizes to content; shrink=1 tolerates tight
  layouts; grow=0 still prevents gap when element has no content.

- .banner ul.nav: overflow: hidden -> overflow: clip. Clips paint without
  creating a scroll container, preserving focus rings on child elements
  (overflow:hidden clips child outlines; overflow:clip does not).

- .sidebar-tooltip-text: add margin-left: 0 to reset the -60px inherited
  from .has-tooltip .tooltip-text. Without this, left: calc(100% + 4px)
  was offset 60px left, placing the tooltip over the trigger element.

Author: BenjaminMichaelis

EssentialCSharp.Web/wwwroot/css/styles.css

@@ -217,7 +217,7 @@ a:hover {
 }
 
 #header-status-host {
-  flex: 0 0 0%;
+  flex: 0 1 auto;
   min-width: 0;
 }
 
@@ -230,7 +230,7 @@ a:hover {
 .banner ul.nav {
   flex-wrap: nowrap;
   max-height: var(--toolbar-height);
-  overflow: hidden;
+  overflow: clip;
   align-items: center;
 }
 
@@ -325,6 +325,7 @@ a:hover {
   position: absolute;
   top: 50%;
   left: calc(100% + 4px);
+  margin-left: 0;
   transform: translateY(-50%);
   border-radius: 10px;
   padding: 10px;