Rediseña panel y auth con la identidad de la landing B2C

- Vista de leads en tarjetas + tabla con toggle (tarjetas por defecto, preferencia persistida)
- Galería de trabajos: gestión en /panel/galeria y bloque público en el funnel
- Selector de tema por reformista (presets + color de marca opcional) aplicado a la landing
- Login y registro rediseñados a pantalla partida 50/50 con foto de reforma
- Enlace "Entrar" funcional en la cabecera del funnel; elimina Navbar muerto
- Unifica tipografía y botones del panel con los tokens de la landing

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

mvp/b2c/src/components/Hero/Hero.tsx

@@ -109,7 +109,10 @@ function LeadForm({ slug }: { slug: string }) {
         role="alert"
         aria-live="polite"
       >
-        <div className="w-16 h-16 bg-black text-white rounded-full flex items-center justify-center mb-2">
+        <div
+          className="w-16 h-16 rounded-full flex items-center justify-center mb-2"
+          style={{ backgroundColor: 'var(--brand, #0a0a0a)', color: 'var(--brand-contrast, #fff)' }}
+        >
           <svg width="28" height="28" viewBox="0 0 32 32" fill="none" aria-hidden="true">
             <path
               d="M6 16l7 7L26 9"
@@ -294,7 +297,7 @@ function LeadForm({ slug }: { slug: string }) {
       {/* Submit */}
       <button
         type="submit"
-        className="btn btn-primary w-full justify-center mt-1 disabled:opacity-50 disabled:cursor-not-allowed disabled:transform-none"
+        className="btn btn-brand w-full justify-center mt-1 disabled:opacity-50 disabled:cursor-not-allowed disabled:transform-none"
         disabled={status === 'loading' || !consentsGranted}
         aria-busy={status === 'loading'}
         aria-disabled={status === 'loading' || !consentsGranted}
@@ -370,7 +373,7 @@ export default function Hero({ slug }: { slug: string }) {
             {/* CTAs */}
             <div className="reveal opacity-0 translate-y-6 transition-all duration-700 ease-out delay-200 flex flex-col sm:flex-row gap-3">
               <button
-                className="btn btn-primary btn-lg w-full sm:w-auto"
+                className="btn btn-brand btn-lg w-full sm:w-auto"
                 onClick={() => document.querySelector('#contact')?.scrollIntoView({ behavior: 'smooth' })}
               >
                 Calcular mi reforma gratis
@@ -433,7 +436,10 @@ export default function Hero({ slug }: { slug: string }) {
             },
           ].map(({ icon, title, description }) => (
             <div key={title} className="flex flex-col gap-4 items-center text-center">
-              <div className="w-12 h-12 rounded-full bg-black flex items-center justify-center text-white">
+              <div
+                className="w-12 h-12 rounded-full flex items-center justify-center"
+                style={{ backgroundColor: 'var(--brand, #0a0a0a)', color: 'var(--brand-contrast, #fff)' }}
+              >
                 {icon}
               </div>
               <h3 className="text-lg font-black tracking-tight text-black">{title}</h3>