feat(legal): SMS opt-in form + Privacy Policy + Terms for Twilio A2P 10DLC

Public, unauthenticated pages required for A2P 10DLC campaign verification:
- /sms-opt-in: web opt-in form (phone field, un-pre-checked consent checkbox,
  message description, frequency, msg&data-rates + HELP/STOP disclaimers, links
  to Terms & Privacy, 'Yes, sign me up!' submit).
- /privacy: Privacy Policy with the mandatory SMS clauses (no third-party/affiliate
  sharing of mobile numbers or SMS consent, message frequency, rates disclosure).
- /terms: Terms of Service with an SMS program-terms section.
Business details centralized in legal-config.ts (replace SMS_SENDER with the
live Twilio number once approved).

src/app/(legal)/layout.tsx

@@ -0,0 +1,45 @@
+import type { Metadata } from "next";
+import Link from "next/link";
+import "@/components/portal/portal.css";
+import "./legal.css";
+import { COMPANY } from "./legal-config";
+
+export const metadata: Metadata = {
+  title: `${COMPANY} — Legal & SMS`,
+  description: `${COMPANY} SMS program opt-in, Privacy Policy and Terms of Service.`,
+};
+
+export default function LegalLayout({ children }: { children: React.ReactNode }) {
+  return (
+    <>
+      <link rel="preconnect" href="https://fonts.googleapis.com" />
+      <link rel="preconnect" href="https://fonts.gstatic.com" crossOrigin="anonymous" />
+      <link
+        href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap"
+        rel="stylesheet"
+      />
+      <div className="legal-root">
+        <header className="legal-bar">
+          <Link href="/portal/login" aria-label={`${COMPANY} home`}>
+            {/* eslint-disable-next-line @next/next/no-img-element */}
+            <img src="/image/logo.png" alt={`${COMPANY} logo`} />
+          </Link>
+          <nav>
+            <Link href="/sms-opt-in">SMS Alerts</Link>
+            <Link href="/privacy">Privacy</Link>
+            <Link href="/terms">Terms</Link>
+          </nav>
+        </header>
+        {children}
+        <footer className="legal-foot">
+          <div>© {new Date().getFullYear()} {COMPANY}. All rights reserved.</div>
+          <div style={{ marginTop: 8 }}>
+            <Link href="/sms-opt-in">SMS Alerts</Link>
+            <Link href="/privacy">Privacy Policy</Link>
+            <Link href="/terms">Terms of Service</Link>
+          </div>
+        </footer>
+      </div>
+    </>
+  );
+}