Header: show the logged-in user with an OIDC / local badge, or (no auth)

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

web/index.html

@@ -41,6 +41,7 @@
         <svg class="sun" viewBox="0 0 24 24"><circle cx="12" cy="12" r="4"/><path d="M12 2v2M12 20v2M4.9 4.9l1.4 1.4M17.7 17.7l1.4 1.4M2 12h2M20 12h2M4.9 19.1l1.4-1.4M17.7 6.3l1.4-1.4"/></svg>
         <svg class="moon" viewBox="0 0 24 24"><path d="M21 12.8A9 9 0 1 1 11.2 3a7 7 0 0 0 9.8 9.8z"/></svg>
       </button>
+      <span id="whoami" class="whoami" hidden><span class="who-name"></span><span class="who-badge"></span></span>
       <a id="logoutBtn" class="icon-btn" href="/auth/logout" hidden data-i18n-title="logout" data-i18n-aria="logout">
         <!-- Log out icon (Lucide "log-out", ISC license) -->
         <svg viewBox="0 0 24 24"><path d="M9 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h4"/><path d="m16 17 5-5-5-5"/><path d="M21 12H9"/></svg>