feat(mobile): gate publish behind subscription, surface free trial

Publishing (including re-publishing after a lapsed subscription —
PRD §15) now checks Pro entitlement first; if inactive, prompts the
owner to the paywall instead of calling the publish endpoint. The
paywall also flags packages with an active introductory offer as
"7 gün ücretsiz dene" (both plans now have a 7-day free trial
configured in App Store Connect, Turkey territory).

apps/mobile/src/app/account/subscription.tsx

@@ -144,6 +144,11 @@ export default function SubscriptionScreen() {
                 <Text style={{ fontSize: 13, color: "#78716C", marginTop: 2 }}>
                   {pkg.product.priceString} / {pkg.packageType === "ANNUAL" ? "yıl" : "ay"}
                 </Text>
+                {pkg.product.introPrice ? (
+                  <Text style={{ fontSize: 12, color: "#059669", fontWeight: "700", marginTop: 2 }}>
+                    7 gün ücretsiz dene
+                  </Text>
+                ) : null}
               </View>
               {purchasingPackageId === pkg.identifier ? (
                 <ActivityIndicator color="#C8A96B" />