Implement admin back-pass flow and guarded admin actions

wwwroot/js/app-auth-handlers.js

@@ -1,6 +1,11 @@
 import { api } from "./api.js";
 import { t } from "./i18n.js";
-import { state, clearUserState, setSavedUsername } from "./state.js";
+import {
+    state,
+    clearUserState,
+    clearSavedUsername,
+    setSavedUsername,
+} from "./state.js";
 import { $, toast } from "./dom.js";
 import {
     handleAuthError,
@@ -139,24 +144,38 @@ function setupLogoutHandler() {
     const logoutBtn = $("logout");
     if (!logoutBtn) return;
 
+    const clearAuthFormFields = () => {
+        [
+            "login-username",
+            "login-password",
+            "register-username",
+            "register-password",
+            "register-displayName",
+            "register-adminkey",
+        ].forEach((id) => {
+            const input = $(id);
+            if (input) input.value = "";
+        });
+
+        ["login-consent", "register-consent"].forEach((id) => {
+            const box = $(id);
+            if (box) box.checked = false;
+        });
+    };
+
     logoutBtn.addEventListener("click", async (e) => {
         e.preventDefault();
-        const lastUser = state.me?.username;
         try {
             await api.logout();
         } catch (err) {
             toast(err.message, true);
         }
         clearUserState();
+        clearSavedUsername();
         state.isAuthenticated = false;
+        setAuthMode("login");
         setAuthUI(false);
-        if (lastUser) {
-            setSavedUsername(lastUser);
-            const loginUser = $("login-username");
-            if (loginUser) loginUser.value = lastUser;
-            const loginPass = $("login-password");
-            if (loginPass) loginPass.value = "";
-        }
+        clearAuthFormFields();
     });
 }