fix(changelog): remove unsupported v1.9.0 'Two-Factor Authentication' entry

The v1.9.0 changelog entry dated 2024-10-30 advertised TOTP-based 2FA
for admin users. The audit (docs/qa/audit-2026-06-26/FINAL-REPORT.md
PROPOSE #1; PROMISE-AUDIT.md #3) found no 2FA implementation: no TOTP
columns, no Better Auth twoFactor plugin registration in
src/lib/auth.ts / src/auth.config.ts.

Two paths were offered: implement Better Auth's twoFactor plugin, or
delete the entry and queue 2FA as a real ticket. Per the user decision
this commit deletes the entry.

- src/app/changelog/page.tsx: removed the v1.9.0 object from CHANGELOG
  array (was the last entry, so trailing comma on v2.0.0 also removed).
- Same file: removed unused 'Shield' import (lucide-react) that was
  only referenced by the deleted entry. react-doctor flags unused
  imports, so this keeps the lint baseline at 0 errors on this file.

No public-facing claims were left behind by this commit:
- /security no longer mentions 2FA (audit commit bb349e4).
- No other code path references v1.9.0.

Scope of this slice was strictly the changelog copy. The 'queue 2FA
as a real ticket' part of the audit recommendation is a separate
decision; flag it in your tracker of choice when ready.

src/app/changelog/page.tsx

@@ -1,5 +1,5 @@
 import type { Metadata, Viewport } from "next";
-import { FileText, Zap, Bug, Shield } from "lucide-react";
+import { FileText, Zap, Bug } from "lucide-react";
 import Link from "next/link";
 
 const BASE_URL = process.env.NEXT_PUBLIC_SITE_URL ?? "https://routecommerce.com";
@@ -96,14 +96,6 @@ const CHANGELOG = [
     description: "Complete redesign of the admin dashboard with improved navigation, faster loading, and better mobile support.",
     icon: Zap,
   },
-  {
-    version: "1.9.0",
-    date: "2024-10-30",
-    category: "security",
-    title: "Two-Factor Authentication",
-    description: "Added 2FA support for enhanced account security. Admin users can now enable TOTP-based authentication.",
-    icon: Shield,
-  },
 ];
 
 const categoryStyles = {