Add Hub web authentication: login page, session middleware, logout button

Agent-Logs-Url: https://github.com/naturallaw777/staging_alpha/sessions/afb996f6-f6f5-4d4a-9f99-e46e3f89b4d7

Co-authored-by: naturallaw777 <99053422+naturallaw777@users.noreply.github.com>

app/sovran_systemsos_web/static/js/events.js

@@ -9,6 +9,12 @@ if ($btnSave) $btnSave.addEventListener("click", saveErrorReport);
 if ($credsCloseBtn) $credsCloseBtn.addEventListener("click", closeCredsModal);
 if ($supportCloseBtn) $supportCloseBtn.addEventListener("click", closeSupportModal);
 
+// Logout button
+if ($logoutBtn) $logoutBtn.addEventListener("click", function () {
+  fetch("/api/logout", { method: "POST", credentials: "same-origin" })
+    .finally(function () { window.location.replace("/login"); });
+});
+
 // Rebuild modal
 if ($rebuildClose) $rebuildClose.addEventListener("click", closeRebuildModal);
 if ($rebuildReboot) $rebuildReboot.addEventListener("click", doReboot);

app/sovran_systemsos_web/static/js/state.js

@@ -59,6 +59,8 @@ const $supportModal     = document.getElementById("support-modal");
 const $supportBody      = document.getElementById("support-body");
 const $supportCloseBtn  = document.getElementById("support-close-btn");
 
+const $logoutBtn = document.getElementById("btn-logout");
+
 // Feature Manager — rebuild modal
 const $rebuildModal    = document.getElementById("rebuild-modal");
 const $rebuildSpinner  = document.getElementById("rebuild-spinner");