Añade gold y transfer: patrón de pago unificado con fulfill + metadata

- lib/stripe.ts: createCheckoutSession acepta metadata; claimPaidCheckout la
  recupera de la sesión Stripe y la devuelve.
- lib/paid-services.ts: config unificado con fulfill(character, meta) + extraFields.
  gold -> UPDATE characters money (BD directa, no SOAP), transfer -> SOAP
  .char changeaccount. Los 5 simples usan soapFulfill.
- checkout [service]: lee extraFields -> metadata, precio depende de metadata (gold),
  valida precio>0. service-success llama cfg.fulfill(name, metadata).
- prices.ts: getTransferPrice, getGoldOptions/goldPriceFor (home_goldprice).
- GoldForm (personaje + cantidad) y TransferForm (personaje + destino); páginas
  /gold y /transfer. Catálogos Paid.gold/transfer.

Verificado: /gold /transfer redirigen a login, checkout 401 sin sesión, home OK.
NOTA: transfer no valida aún el token de seguridad ni reglas AC (nivel>=55, DK).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

web-next/components/GoldForm.tsx

@@ -0,0 +1,64 @@
+'use client'
+
+import { useState } from 'react'
+import { useTranslations } from 'next-intl'
+import type { GoldOption } from '@/lib/prices'
+
+export function GoldForm({ characters, options }: { characters: string[]; options: GoldOption[] }) {
+  const t = useTranslations('Services')
+  const tp = useTranslations('Paid')
+  const [character, setCharacter] = useState('')
+  const [amount, setAmount] = useState('')
+  const [busy, setBusy] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  async function handleSubmit(e: React.FormEvent) {
+    e.preventDefault()
+    if (busy || !character || !amount) return
+    setBusy(true)
+    setError(null)
+    try {
+      const res = await fetch('/api/character/gold/checkout', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        credentials: 'same-origin',
+        body: JSON.stringify({ character, gold_amount: amount }),
+      })
+      const data: { success?: boolean; url?: string } = await res.json()
+      if (data.success && data.url) window.location.href = data.url
+      else {
+        setError(t('genericError'))
+        setBusy(false)
+      }
+    } catch {
+      setError(t('genericError'))
+      setBusy(false)
+    }
+  }
+
+  const field = 'w-full rounded border border-amber-900/60 bg-[#2c1e14] px-3 py-2'
+  if (characters.length === 0) return <p className="text-amber-200/70">{t('noCharactersYet')}</p>
+
+  return (
+    <div className="mx-auto max-w-sm text-center">
+      <form onSubmit={handleSubmit} className="space-y-3">
+        <select value={character} onChange={(e) => setCharacter(e.target.value)} required className={field}>
+          <option value="" disabled>{t('selectCharacter')}</option>
+          {characters.map((c) => <option key={c} value={c}>{c}</option>)}
+        </select>
+        <select value={amount} onChange={(e) => setAmount(e.target.value)} required className={field}>
+          <option value="" disabled>{tp('gold.selectAmount')}</option>
+          {options.map((o) => (
+            <option key={o.gold_amount} value={o.gold_amount}>
+              {tp('gold.option', { amount: o.gold_amount, price: o.price })}
+            </option>
+          ))}
+        </select>
+        <button type="submit" disabled={busy || !character || !amount} className="w-full rounded bg-amber-600 px-4 py-2 font-semibold text-[#1b120b] disabled:opacity-60">
+          {busy ? t('processing') : tp('gold.buy')}
+        </button>
+      </form>
+      {error && <p className="mt-3 text-red-400">{error}</p>}
+    </div>
+  )
+}

web-next/components/ServicePageContent.tsx

@@ -17,7 +17,7 @@ export async function ServicePageContent({ service, locale }: { service: string;
   if (!session.bnetId) redirect({ href: '/login', locale })
   if (!session.username) redirect({ href: '/select-account', locale })
 
-  const [chars, price] = await Promise.all([getGameCharacters(session.accountId!), cfg!.getPrice()])
+  const [chars, price] = await Promise.all([getGameCharacters(session.accountId!), cfg!.price({})])
 
   return (
     <main className="mx-auto max-w-3xl px-4 py-8">

web-next/components/TransferForm.tsx

@@ -0,0 +1,56 @@
+'use client'
+
+import { useState } from 'react'
+import { useTranslations } from 'next-intl'
+
+export function TransferForm({ characters, price }: { characters: string[]; price: number }) {
+  const t = useTranslations('Services')
+  const tp = useTranslations('Paid')
+  const [character, setCharacter] = useState('')
+  const [destination, setDestination] = useState('')
+  const [busy, setBusy] = useState(false)
+  const [error, setError] = useState<string | null>(null)
+
+  async function handleSubmit(e: React.FormEvent) {
+    e.preventDefault()
+    if (busy || !character || !destination.trim()) return
+    setBusy(true)
+    setError(null)
+    try {
+      const res = await fetch('/api/character/transfer/checkout', {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        credentials: 'same-origin',
+        body: JSON.stringify({ character, destination_account: destination.trim() }),
+      })
+      const data: { success?: boolean; url?: string } = await res.json()
+      if (data.success && data.url) window.location.href = data.url
+      else {
+        setError(t('genericError'))
+        setBusy(false)
+      }
+    } catch {
+      setError(t('genericError'))
+      setBusy(false)
+    }
+  }
+
+  const field = 'w-full rounded border border-amber-900/60 bg-[#2c1e14] px-3 py-2'
+  if (characters.length === 0) return <p className="text-amber-200/70">{t('noCharactersYet')}</p>
+
+  return (
+    <div className="mx-auto max-w-sm text-center">
+      <form onSubmit={handleSubmit} className="space-y-3">
+        <select value={character} onChange={(e) => setCharacter(e.target.value)} required className={field}>
+          <option value="" disabled>{t('selectCharacter')}</option>
+          {characters.map((c) => <option key={c} value={c}>{c}</option>)}
+        </select>
+        <input type="text" placeholder={tp('transfer.destination')} value={destination} onChange={(e) => setDestination(e.target.value)} required className={field} />
+        <button type="submit" disabled={busy || !character || !destination.trim()} className="w-full rounded bg-amber-600 px-4 py-2 font-semibold text-[#1b120b] disabled:opacity-60">
+          {busy ? t('processing') : tp('transfer.pay', { price })}
+        </button>
+      </form>
+      {error && <p className="mt-3 text-red-400">{error}</p>}
+    </div>
+  )
+}