iap: wire coin packs to Cafe Bazaar SKUs + auto-select Bazaar billing in the APK

- Pack ids now equal the Bazaar/Myket SKUs (Coin5K / Coin12K / Coin28K /
  Coin65K) in both the server source-of-truth (ProfileService.Packs) and the
  mock, so the IAB credit path (Id == ProductId) grants the right coins.
  Coin totals + prices already matched the registered products.
- storeBilling.getStore(): when running inside the Capacitor Android shell and
  no explicit NEXT_PUBLIC_STORE flavor is set, default to "bazaar" so the APK
  uses Cafe Bazaar IAB (the web build stays on the ZarinPal gateway). Myket's
  native bridge still overrides when present.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/lib/storeBilling.ts

@@ -28,11 +28,20 @@ interface MyketBridge {
 declare global {
   interface Window {
     MyketBilling?: MyketBridge;
+    Capacitor?: { isNativePlatform?: () => boolean; getPlatform?: () => string };
   }
 }
 
 export function getStore(): StoreId {
-  if (typeof window !== "undefined" && window.MyketBilling?.available) return "myket";
+  if (typeof window === "undefined") return ENV_STORE;
+  // Myket's native bridge wins when present (a Myket-flavored build).
+  if (window.MyketBilling?.available) return "myket";
+  // Honor an explicit build flavor.
+  if (ENV_STORE !== "web") return ENV_STORE;
+  // Otherwise, inside the Android app shell (Capacitor) default to Cafe Bazaar
+  // IAB — the APK ships to Bazaar, which requires its own billing. The web build
+  // stays on the web (ZarinPal) gateway.
+  if (window.Capacitor?.isNativePlatform?.()) return "bazaar";
   return ENV_STORE;
 }