Let the store take PRO back, and finish every purchase

src/utils/proUnlock.ts

@@ -50,6 +50,11 @@ const grant = async () => {
   await AsyncStorage.setItem(CACHE_KEY, '1').catch(() => {});
 };
 
+const revoke = async () => {
+  set({ owned: false, error: null });
+  await AsyncStorage.removeItem(CACHE_KEY).catch(() => {});
+};
+
 // Play hands the purchase to the listener. Grant it, then finalise: an Android
 // purchase left unacknowledged for three days is automatically refunded.
 // ponytail: the grant is client-side. Server-side verification of
@@ -80,7 +85,19 @@ export async function initProUnlock() {
     ]);
     const listed = (Array.isArray(products) ? products : []).find((p) => p.id === PRO_SKU);
     set({ price: listed?.displayPrice ?? null });
-    if (purchases.some((p) => p.productId === PRO_SKU)) await grant();
+    const bought = purchases.find((p) => p.productId === PRO_SKU);
+    if (bought) {
+      await grant();
+      // A purchase Play never got from us finalised (the app was killed between
+      // the two) is refunded automatically after three days. Harmless to repeat.
+      await finishTransaction({ purchase: bought as never, isConsumable: false }).catch(() => {});
+    } else if (listed) {
+      // The store is the authority: a refunded purchase is no longer in the
+      // list, so the cache must not outlive it. Only when the query ANSWERED and
+      // the product is still on sale — an offline or broken query also returns
+      // nothing, and that must never revoke a paying user.
+      await revoke();
+    }
   } catch (e) {
     set({ error: e instanceof Error ? e.message : 'Store unavailable' });
   }