refactor(billing): remove Stripe; payments are Payple (web) and Google Play (mobile)

Stripe is not used. Keeping its checkout, portal and webhook paths meant a
second payment provider, a second return-URL format and dead UI.

- Delete the stripe-checkout, stripe-portal and stripe-webhook functions and
  their config; billing-catalog serves Payple prices only, and the web parser
  rejects a catalog that still mixes in Stripe prices.
- Web: drop the Stripe checkout/portal buttons, provider toggle and return
  notices; billing shows Payple only. Past rows with provider='stripe' are
  still displayed ("Stripe (종료)") with a support contact instead of a portal.
- Desktop: delete the Stripe checkout modal, payment IPC channels, preload
  namespace and their types; "Remove ads with Pro" opens the web billing page
  via license.openBilling. Support/refund copy names Payple.
- billingUrl() loses the Stripe-only success/canceled result option; the
  Deno contract is regenerated.
- Migrations and the DB's accepted provider values are untouched (history).
- Docs and the backlog record the removal (MON-04, EXT-STRIPE-01, GAP-BILL-03).

Verified: typecheck (desktop/web/admin/api-client/mobile), contract:check,
deno check all functions, deno test 80/80, desktop 1478/1480 on the Electron
runtime (2 known environment failures), web and admin builds, release
metadata and mobile boundary self-tests, eslint on changed files.

apps/web/src/components/billing/billing-checkout-options.tsx

@@ -1,12 +1,11 @@
 'use client'
 
-import { useMemo, useState } from 'react'
-import { Alert, Box, ToggleButton, ToggleButtonGroup, Typography } from '@mui/material'
-import { CheckoutButton } from './checkout-button'
+import { Alert, Box } from '@mui/material'
 import { PaypleCheckoutButton } from './payple-checkout-button'
 import type { PaypleTier } from './payple-client'
-import type { BillingCatalogPrice, WebBillingProvider } from '@/lib/billing-catalog'
+import type { BillingCatalogPrice } from '@/lib/billing-catalog'
 
+/** 웹 결제 진입점. 결제사는 Payple(KRW) 하나이며 가격은 billing-catalog 응답을 따른다. */
 export function BillingCheckoutOptions({
   tier,
   prices
@@ -14,48 +13,12 @@ export function BillingCheckoutOptions({
   tier: PaypleTier
   prices: BillingCatalogPrice[]
 }): React.ReactElement {
-  const availableProviders = useMemo(() => new Set(prices.map((price) => price.provider)), [prices])
-  const initialProvider: WebBillingProvider = availableProviders.has('payple') ? 'payple' : 'stripe'
-  const [provider, setProvider] = useState<WebBillingProvider>(initialProvider)
-  const payplePrice = prices.find((price): price is BillingCatalogPrice & { provider: 'payple' } => (
-    price.provider === 'payple'
-  ))
+  const payplePrice = prices.find((price) => price.provider === 'payple')
 
   return (
     <Box data-testid={`billing-checkout-${tier}`}>
-      <Typography sx={{ mb: 1, color: 'var(--d3-text-label)', fontSize: 11 }}>
-        결제 수단을 선택해 주세요. 한 구독에는 하나의 결제사만 사용할 수 있습니다.
-      </Typography>
-      <ToggleButtonGroup
-        exclusive
-        fullWidth
-        size="small"
-        value={provider}
-        onChange={(_event, value: WebBillingProvider | null) => {
-          if (value !== null && availableProviders.has(value)) setProvider(value)
-        }}
-        aria-label="결제사 선택"
-        sx={{ mb: 1.5 }}
-      >
-        <ToggleButton value="payple" aria-label="Payple 국내 카드" disabled={!availableProviders.has('payple')}>
-          국내 카드 · Payple
-        </ToggleButton>
-        <ToggleButton value="stripe" aria-label="Stripe 해외 카드" disabled={!availableProviders.has('stripe')}>
-          해외 카드 · Stripe
-        </ToggleButton>
-      </ToggleButtonGroup>
-
-      {provider === 'payple' ? (
-        payplePrice ? <PaypleCheckoutButton tier={tier} catalogPrice={payplePrice} /> : (
-          <Alert severity="error">Payple 가격을 확인할 수 없습니다.</Alert>
-        )
-      ) : (
-        <>
-          <Alert severity="info" variant="outlined" sx={{ mb: 1, fontSize: 11 }}>
-            Stripe Checkout으로 이동해 해외 발급 카드를 결제합니다.
-          </Alert>
-          <CheckoutButton tier={tier} />
-        </>
+      {payplePrice ? <PaypleCheckoutButton tier={tier} catalogPrice={payplePrice} /> : (
+        <Alert severity="error">Payple 가격을 확인할 수 없습니다.</Alert>
       )}
     </Box>
   )

apps/web/src/components/billing/checkout-button.tsx

@@ -1,91 +0,0 @@
-'use client'
-
-// apps/web/src/components/billing/checkout-button.tsx
-// Stripe Checkout 시작 — Edge Function stripe-checkout 호출
-
-import { useState } from 'react'
-import { Button, CircularProgress, Alert, Box } from '@mui/material'
-import { getSupabaseBrowserClient } from '@/lib/supabase-browser'
-import { browserBillingUrl } from '@/lib/web-app-url'
-import type { PaypleTier } from './payple-client'
-
-interface CheckoutButtonProps {
-  tier: PaypleTier
-}
-
-export function CheckoutButton({ tier }: CheckoutButtonProps): React.ReactElement {
-  const [busy, setBusy] = useState(false)
-  const [error, setError] = useState<string | null>(null)
-
-  async function handleCheckout(): Promise<void> {
-    setError(null)
-    setBusy(true)
-    try {
-      const supabase = getSupabaseBrowserClient()
-      const {
-        data: { session },
-        error: sessionError
-      } = await supabase.auth.getSession()
-
-      if (sessionError || !session) {
-        setError('로그인이 필요합니다')
-        return
-      }
-
-      const baseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL?.trim()
-      if (!baseUrl) throw new Error('결제 서버 설정이 완료되지 않았습니다')
-      const endpoint = new URL('/functions/v1/stripe-checkout', baseUrl).toString()
-
-      const response = await fetch(
-        endpoint,
-        {
-          method: 'POST',
-          headers: {
-            Authorization: `Bearer ${session.access_token}`,
-            'Content-Type': 'application/json'
-          },
-          body: JSON.stringify({
-            tier,
-            idempotency_key: `stripe-checkout:${crypto.randomUUID()}`,
-            success_url: browserBillingUrl('success'),
-            cancel_url: browserBillingUrl('canceled')
-          })
-        }
-      )
-
-      const data = (await response.json().catch(() => null)) as { url?: unknown } | null
-      if (!response.ok) throw new Error('Stripe Checkout을 시작하지 못했습니다')
-      if (typeof data?.url !== 'string') throw new Error('Checkout URL을 받지 못했습니다')
-      const checkoutUrl = new URL(data.url)
-      if (checkoutUrl.protocol !== 'https:' || checkoutUrl.hostname !== 'checkout.stripe.com') {
-        throw new Error('Checkout URL을 신뢰할 수 없습니다')
-      }
-      window.location.assign(checkoutUrl.toString())
-    } catch (e) {
-      setError(e instanceof Error ? e.message : 'Unknown error')
-    } finally {
-      setBusy(false)
-    }
-  }
-
-  return (
-    <Box>
-      <Button
-        fullWidth
-        variant="contained"
-        size="large"
-        data-testid={`stripe-upgrade-${tier}`}
-        onClick={() => void handleCheckout()}
-        disabled={busy}
-        startIcon={busy ? <CircularProgress size={16} color="inherit" /> : null}
-      >
-        {tier === 'pro_plus' ? 'PRO+' : 'PRO'} Stripe로 업그레이드
-      </Button>
-      {error && (
-        <Alert severity="error" variant="outlined" sx={{ mt: 1, fontSize: 11 }}>
-          {error}
-        </Alert>
-      )}
-    </Box>
-  )
-}

apps/web/src/components/billing/portal-button.tsx

@@ -1,82 +0,0 @@
-'use client'
-
-// apps/web/src/components/billing/portal-button.tsx
-// Stripe Customer Portal — 활성 구독 사용자가 결제 수단/취소 등을 관리
-
-import { useState } from 'react'
-import { Button, CircularProgress, Alert, Box } from '@mui/material'
-import SettingsIcon from '@mui/icons-material/Settings'
-import { getSupabaseBrowserClient } from '@/lib/supabase-browser'
-import { browserBillingUrl } from '@/lib/web-app-url'
-
-export function PortalButton(): React.ReactElement {
-  const [busy, setBusy] = useState(false)
-  const [error, setError] = useState<string | null>(null)
-
-  async function handleOpenPortal(): Promise<void> {
-    setError(null)
-    setBusy(true)
-    try {
-      const supabase = getSupabaseBrowserClient()
-      const {
-        data: { session },
-        error: sessionError
-      } = await supabase.auth.getSession()
-
-      if (sessionError || !session) {
-        setError('로그인이 필요합니다')
-        return
-      }
-
-      const baseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL?.trim()
-      if (!baseUrl) throw new Error('결제 서버 설정이 완료되지 않았습니다')
-
-      const response = await fetch(
-        new URL('/functions/v1/stripe-portal', baseUrl).toString(),
-        {
-          method: 'POST',
-          headers: {
-            Authorization: `Bearer ${session.access_token}`,
-            'Content-Type': 'application/json'
-          },
-          body: JSON.stringify({
-            return_url: browserBillingUrl()
-          })
-        }
-      )
-
-      const data = await response.json().catch(() => null) as { url?: unknown } | null
-      if (!response.ok) throw new Error('Stripe 구독 관리 페이지를 열지 못했습니다')
-      if (typeof data?.url !== 'string') throw new Error('구독 관리 URL을 받지 못했습니다')
-      const portalUrl = new URL(data.url)
-      if (portalUrl.protocol !== 'https:' || portalUrl.hostname !== 'billing.stripe.com') {
-        throw new Error('구독 관리 URL을 신뢰할 수 없습니다')
-      }
-      window.location.assign(portalUrl.toString())
-    } catch (e) {
-      setError(e instanceof Error ? e.message : 'Unknown error')
-    } finally {
-      setBusy(false)
-    }
-  }
-
-  return (
-    <Box>
-      <Button
-        variant="outlined"
-        size="small"
-        data-testid="stripe-portal-open"
-        startIcon={busy ? <CircularProgress size={14} /> : <SettingsIcon />}
-        onClick={() => void handleOpenPortal()}
-        disabled={busy}
-      >
-        구독 관리
-      </Button>
-      {error && (
-        <Alert severity="error" variant="outlined" sx={{ mt: 1, fontSize: 11 }}>
-          {error}
-        </Alert>
-      )}
-    </Box>
-  )
-}