Add log out support

logout.js

@@ -0,0 +1,21 @@
+$(document).ready(function () {
+    const form = $("#logout-form");
+    if (typeof CONFIG === 'undefined') {
+        alert("CRITICAL ERROR: config.js not loaded before logout.js");
+        return;
+    }
+
+    const apiBase = CONFIG.API_BASE_URL;
+    const targetAction = apiBase.replace(/\/$/, "") + "/spfn/logout";
+    $("#logout_frontend_origin").val(window.location.origin);
+    form.attr("action", targetAction);
+    
+    console.log("Form action set to: " + targetAction);
+
+    form.submit(function(e) {
+        alert("Submitting to: " + $(this).attr("action"));
+        
+        const submitBtn = $(":submit", this);
+        submitBtn.prop("disabled", true).css("opacity", "0.5");
+    });
+});