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.ts

@@ -1,6 +1,8 @@
 // server/supabase/functions/_shared/payple.ts
 // Payple 결제 API 래퍼 — 파트너 인증, 빌링 결제, 취소, 빌링키 해지
 
+import { PLAN_PRICE_KRW } from './core-contract.generated.ts'
+
 // ── 타입 ──────────────────────────────────────────────
 
 export interface PaypleConfig {
@@ -543,9 +545,10 @@ export function calcSubscriptionPeriod(now = new Date()): { start: string; end:
 
 // ── 티어별 가격 ──────────────────────────────────────
 
+/** Payple 청구 금액(원). 정본은 packages/core/src/plan-catalog.ts (생성 사본 경유). */
 export const TIER_PRICE: Record<string, number> = {
-  pro: 9900,
-  pro_plus: 29900,
+  pro: PLAN_PRICE_KRW.pro,
+  pro_plus: PLAN_PRICE_KRW.pro_plus,
 }
 
 export const TIER_GOODS_NAME: Record<string, string> = {