feat: implement settings layout and navigation, add tag and thought pages with API integration

thoughts-frontend/app/settings/layout.tsx

@@ -0,0 +1,35 @@
+// app/settings/layout.tsx
+import { SettingsNav } from "@/components/settings-nav";
+import { Separator } from "@/components/ui/separator";
+
+const sidebarNavItems = [
+  {
+    title: "Profile",
+    href: "/settings/profile",
+  },
+  // You can add more links here later, e.g., "Account", "API Keys"
+];
+
+export default function SettingsLayout({
+  children,
+}: {
+  children: React.ReactNode;
+}) {
+  return (
+    <div className="container mx-auto max-w-5xl space-y-6 p-10 pb-16">
+      <div className="space-y-0.5">
+        <h2 className="text-2xl font-bold tracking-tight">Settings</h2>
+        <p className="text-muted-foreground">
+          Manage your account settings and profile.
+        </p>
+      </div>
+      <Separator className="my-6" />
+      <div className="flex flex-col space-y-8 lg:flex-row lg:space-x-12 lg:space-y-0">
+        <aside className="-mx-4 lg:w-1/5">
+          <SettingsNav items={sidebarNavItems} />
+        </aside>
+        <div className="flex-1 lg:max-w-2xl">{children}</div>
+      </div>
+    </div>
+  );
+}