feat(themes): Terrakotta replaces High Contrast; equal header buttons on phones

chore(release): v0.12.0

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/App.tsx

@@ -864,11 +864,14 @@ export const App: React.FC = () => {
                 triggerHaptic(10);
                 setShowCommandPalette(true);
               }}
-              className="w-11 h-11 rounded-full flex items-center justify-center text-muted hover:text-main bg-panel border border-border transition-transform active:scale-95 cursor-pointer"
+              className="w-11 h-11 rounded-full flex items-center justify-center text-muted hover:text-main transition-transform active:scale-95 cursor-pointer"
               title="Globale Suche"
               aria-label="Globale Suche öffnen"
             >
-              <Search className="w-4 h-4" />
+              {/* Same visible size as the avatar next to it; the 44px button stays the touch target */}
+              <span className="w-9 h-9 rounded-full flex items-center justify-center bg-panel border border-border">
+                <Search className="w-4 h-4" />
+              </span>
             </button>
 
             <button
@@ -884,7 +887,7 @@ export const App: React.FC = () => {
               }`}
               title="Profil & Einstellungen"
             >
-              <UserAvatar user={user} size="sm" className="shadow-sm" />
+              <UserAvatar user={user} size="md" className="shadow-sm" />
             </button>
           </div>
         </div>