feat(admin): implement pricing overrides for plans and update pricing logic

apps/backend/src/modules/plan/handlers/list-plans.handler.ts

@@ -1,4 +1,6 @@
+import { fetchGeoInfo } from '@/lib/geoip';
 import { db } from '@/lib/prisma';
+import { resolvePlanPrice } from '@/modules/plan/services/plan-pricing.service';
 import { parsePlanRules } from '@/modules/plan/services/plan-rules.service';
 import type { AppContext } from '@/types/hono';
 
@@ -9,13 +11,26 @@ export async function listPlansHandler(c: AppContext) {
     },
   });
 
+  const countryParam = c.req.query('country');
+  let countryCode: string | undefined;
+
+  if (countryParam) {
+    countryCode = countryParam;
+  } else {
+    const ip = c.req.header('x-forwarded-for')?.split(',')[0]?.trim() || '127.0.0.1';
+    const geo = await fetchGeoInfo(ip);
+    countryCode = geo?.countryCode || undefined;
+  }
+
   return c.json(
     plans.map((plan) => {
       const rules = parsePlanRules(plan.rules);
+      const resolved = resolvePlanPrice(Number(plan.price), rules, countryCode);
       return {
         code: plan.code,
         name: plan.name,
-        price: Number(plan.price),
+        price: resolved.amount,
+        currency: resolved.currency,
         features: rules.features,
         limits: rules.limits,
       };

apps/backend/src/modules/plan/services/plan-pricing.service.ts

@@ -0,0 +1,25 @@
+import type { PlanRules } from '@repo/api-contract';
+
+export type PlanPrice = {
+  amount: number;
+  currency: string;
+};
+
+export function resolvePlanPrice(
+  defaultPrice: number,
+  rules: PlanRules,
+  countryCode?: string
+): PlanPrice {
+  if (!countryCode) {
+    return { amount: defaultPrice, currency: 'USD' };
+  }
+
+  if (rules.version === 'v2' && rules.pricing?.overrides) {
+    const override = rules.pricing.overrides[countryCode];
+    if (override) {
+      return { amount: override.amount, currency: override.currency };
+    }
+  }
+
+  return { amount: defaultPrice, currency: 'USD' };
+}