refactor(core): keep plan prices, cloud quotas and public URLs in one contract (WS-A)

Prices, quotas and site URLs were copied by hand into the edge functions,
admin, desktop and the landing site, and the copies disagreed (Payple billed
9,900/29,900 KRW, admin labels said 12,900/24,900 KRW and $9.9/$19.9, the
site said 2,900/8,900 KRW).

- packages/core/src/plan-catalog.ts is the single source for PLAN_PRICE_KRW
  (Free 0 / Pro 2,900 / Pro+ 8,900 a month) and PLAN_QUOTA.
- packages/core/src/web-urls.ts is the single source for the public origin,
  the /app web-app base path, SITE_URLS and billingUrl().
- Deno cannot bundle packages/core, so scripts/ci/sync-core-contract.mjs
  generates _shared/core-contract.generated.ts; `npm run contract:check`
  fails on drift (same pattern as version:sync).
- Payple checkout, renewal and webhook amount checks now bill the catalog
  price, so existing subscribers move to the new price at their next renewal.
  quota.ts, team-contract.ts and the tests read the generated values.
- Admin MRR/ARR is computed in KRW from the catalog; license labels, the
  release link and desktop PREMIUM_LLM limits derive from core; the site
  imports prices and quotas directly.

Policy: docs/REFACTOR_POLICY.md Wave 3, W3-1 and W3-2.

server/supabase/functions/_shared/payple.test.ts

@@ -11,7 +11,9 @@ import {
   PaypleConfigurationError,
   PaypleVerificationError,
   resolvePaypleOrderDate,
+  TIER_PRICE,
 } from './payple.ts'
+import { PLAN_PRICE_KRW } from './core-contract.generated.ts'
 
 function assert(condition: boolean, message: string): asserts condition {
   if (!condition) throw new Error(message)
@@ -90,11 +92,11 @@ Deno.test('Payple synchronous charge and webhook share one provider event identi
     orderId: 'D3RO-20260821153045-test-nonce',
     payerId: 'payer-fixture',
     payType: 'card' as const,
-    amount: 9900,
+    amount: TIER_PRICE.pro,
   }
   const directDigest = await payplePaymentEventDigest(identity)
   const webhookDigest = await payplePaymentEventDigest({ ...identity })
-  const differentCharge = await payplePaymentEventDigest({ ...identity, amount: 29900 })
+  const differentCharge = await payplePaymentEventDigest({ ...identity, amount: TIER_PRICE.pro_plus })
   assert(payplePaymentEventId(identity.orderId) === `payment:${identity.orderId}`, 'canonical event id')
   assert(directDigest === webhookDigest, 'same external charge must be an exact replay')
   assert(directDigest !== differentCharge, 'different charge identity must not collide')
@@ -163,7 +165,7 @@ Deno.test('Payple billing separates definitive declines from ambiguous transport
       try {
         await paypleBilling(config, auth, {
           payerId: 'payer-fixture',
-          amount: 9900,
+          amount: TIER_PRICE.pro,
           orderId: 'D3RO-20260821153045-test-nonce',
           goodsName: 'D3RO Voice Pro',
         })
@@ -177,3 +179,9 @@ Deno.test('Payple billing separates definitive declines from ambiguous transport
     globalThis.fetch = originalFetch
   }
 })
+
+Deno.test('Payple charge amounts are the core plan catalog prices', () => {
+  assert(TIER_PRICE.pro === PLAN_PRICE_KRW.pro, 'Pro charge must equal PLAN_PRICE_KRW.pro')
+  assert(TIER_PRICE.pro_plus === PLAN_PRICE_KRW.pro_plus, 'Pro+ charge must equal PLAN_PRICE_KRW.pro_plus')
+  assert(Object.keys(TIER_PRICE).sort().join(',') === 'pro,pro_plus', 'only paid tiers are chargeable')
+})