style: badges centered to flags, wider dashboard, mobile header actions

MatchCard:
- Badges (group, countdown, LIVE, BEENDET) now vertically centered
  to flag height, positioned left/right of the teams
- Removed separate topRow — all in one matchBlock flex layout

Dashboard:
- max-width increased to 800px (matches spielplan width)

Header:
- Theme toggle + admin link moved to headerActions (always visible)
- Theme toggle icon in gold color (was too dark in dark mode)
- Admin link brighter (text-secondary instead of text-muted)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/App.module.css

@@ -85,8 +85,8 @@
   font-size: 16px;
   cursor: pointer;
   transition: background 0.15s, transform 0.1s;
-  margin-left: 6px;
   flex-shrink: 0;
+  color: var(--gold);
 }
 .themeToggle:hover { background: var(--primary-dim); }
 .themeToggle:active { transform: scale(0.92); }
@@ -106,19 +106,26 @@
   }
 }
 
-/* Hide header nav on mobile */
+/* Header actions — always visible (theme toggle + admin) */
+.headerActions {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+/* Hide header nav on mobile, keep actions */
 @media (max-width: 767px) {
   .nav {
     display: none;
   }
 }
 
-/* Admin link: icon only, subtle */
+/* Admin link: icon only */
 .adminLink {
   display: flex;
   align-items: center;
   padding: 4px;
-  color: var(--text-muted);
+  color: var(--text-secondary);
   text-decoration: none;
   transition: color 0.2s;
 }