Replace Vazirmatn with a locally-served Peyda font for Persian text.

Vendor the Peyda woff weights (Thin–Black) under public/fonts/peyda and
load them via next/font/local in a shared fonts module, exposed through
the --font-peyda CSS variable and the font-peyda Tailwind utility. Drops
the runtime Google Fonts fetch on the landing and auth pages.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/auth/AuthShell.tsx

@@ -1,10 +1,8 @@
 import type { ReactNode } from 'react';
-import { Vazirmatn } from 'next/font/google';
 import Link from 'next/link';
+import { peyda } from '@/app/fonts';
 import { Logo } from '@/components/landing/Logo';
 
-const vazir = Vazirmatn({ subsets: ['arabic'], variable: '--font-vazir', display: 'swap' });
-
 // Cinematic auth shell that echoes the Abrban landing: a calm blue sky (the
 // "clear sky" finale), soft drifting clouds, a warm sun glow, the brand logo,
 // and the form inside a frosted dark-glass panel. Persian / RTL.
@@ -28,7 +26,7 @@ export function AuthShell({
   return (
     <div
       dir="rtl"
-      className={`${vazir.variable} font-vazir relative min-h-screen w-full overflow-hidden bg-gradient-to-b from-[#1b6fd0] via-[#589add] to-[#cfe6f7] text-white`}
+      className={`${peyda.variable} font-peyda relative min-h-screen w-full overflow-hidden bg-gradient-to-b from-[#1b6fd0] via-[#589add] to-[#cfe6f7] text-white`}
     >
       {/* Sky atmosphere: warm sun glow, drifting clouds, soft vignette */}
       <div className="pointer-events-none absolute inset-0 overflow-hidden">