feat(ops-web/auth): add remember-me with session/local storage split

Persistent logins land in localStorage, ephemeral ones in sessionStorage,
and we recall the last username + remember preference on the login form.
Also propagate the indigo brand color through the antd ConfigProvider
theme token so the side nav and avatar match the redesigned login.

apps/ops-web/src/layouts/AppShell.vue

@@ -138,14 +138,14 @@ onMounted(() => {
 
 .ops-brand {
   height: 40px;
-  background: #f0f8ff;
-  border: 1px solid #bae0ff;
+  background: #eef2ff;
+  border: 1px solid #c7d2fe;
   margin: 16px;
   border-radius: 6px;
   display: flex;
   align-items: center;
   justify-content: center;
-  color: #1677ff;
+  color: #4f46e5;
   font-weight: 800;
   font-size: 16px;
   letter-spacing: 0.05em;
@@ -195,7 +195,7 @@ onMounted(() => {
 }
 
 .user-avatar {
-  background-color: #1677ff;
+  background-color: #4f46e5;
   color: #fff;
   width: 28px;
   height: 28px;