Drop the in-app unlock key: only the PRO apk opens PRO

The set is two apks and the unlock key was a second, weaker lock on the
same door. A verifier that runs offline has to carry its secret inside
the lite apk, so anyone who unpacked it could mint a key. Nothing in the
lite build can flip the gate now.

- entitlement.ts keeps the gate (which look is PRO, what an export
  carries in lite) and exports IS_PRO straight from the build flag.
- SETTINGS loses the key field; the plan chip still says LITE / PRO
  ACTIVE and the helper text says what lite cannot export.
- The upsell alerts just name the build that has the feature.
- tools/keygen.mjs goes with the verifier it fed.

App.tsx

@@ -26,7 +26,7 @@ import { processAndExportPhoto } from './src/utils/exportEngine';
 import { processAndExportPhotoNative } from './src/utils/nativeExport';
 import { exportRecipeXml, importRecipeXml } from './src/utils/recipeShare';
 import { PARAM_DEFS } from './src/utils/paramDefs';
-import { LITE_MARK, LITE_RECIPE_LIMIT, activatePro, loadPro, proLookInUse } from './src/utils/entitlement';
+import { IS_PRO, LITE_MARK, LITE_RECIPE_LIMIT, proLookInUse } from './src/utils/entitlement';
 import UltraWide from './modules/recipescam-ultrawide';
 
 // @ts-ignore
@@ -97,12 +97,8 @@ export default function App() {
     };
   }, []);
   const [recipes, setRecipes] = useState<Recipe[]>([]);
-  // Lite (free) vs PRO (unlocked key). Read once at startup; the unlock key
-  // flips it in place, so every later export drops the mark and the look gate.
-  const [pro, setPro] = useState(false);
-  useEffect(() => {
-    loadPro().then(setPro);
-  }, []);
+  // LITE (free) vs PRO (the paid build): fixed for the life of the install.
+  const pro = IS_PRO;
   // Lite stores up to LITE_RECIPE_LIMIT recipes of its own; past that the save
   // paths ask for PRO. Deleting one is PRO as well, so a Lite list only grows.
   const customRecipeCount = recipes.filter((r) => r.isCustom).length;
@@ -1035,41 +1031,20 @@ export default function App() {
   // The native Kotlin exporter has no text-watermark draw, so a Lite export
   // (which always carries the mark) must take the Skia engine.
   const nativeExport = NATIVE_EXPORT && pro;
-  // Shutter/export with a PRO look: nothing is rendered — name the feature and
-  // point at the unlock.
+  // Shutter/export with a PRO look: nothing is rendered — name the feature so
+  // the user knows which PRO build would render it.
   const promptPro = (feature: string) => {
     Haptics.notificationAsync(Haptics.NotificationFeedbackType.Warning);
     Alert.alert(
       'PRO LOOK',
-      `${feature} can be previewed and edited for free, but exporting it needs PRO. Your own key unlocks it in SETTINGS.`,
-      [
-        { text: 'LATER', style: 'cancel' },
-        { text: 'SETTINGS', onPress: () => setSettingsVisible(true) },
-      ]
+      `${feature} can be previewed and edited for free, but exporting it needs the PRO build.`
     );
   };
-  // Saving, starring, spawning: the action IS the feature, so there is no
-  // look to preview first — a Lite tap names it and points at the unlock,
-  // and nothing else happens.
+  // Saving, starring, spawning: the action IS the feature, so there is no look
+  // to preview first — a LITE tap names it and nothing else happens.
   const promptProFeature = (feature: string) => {
     Haptics.notificationAsync(Haptics.NotificationFeedbackType.Warning);
-    Alert.alert(
-      'PRO FEATURE',
-      `${feature} needs PRO. Your own key unlocks it in SETTINGS.`,
-      [
-        { text: 'LATER', style: 'cancel' },
-        { text: 'SETTINGS', onPress: () => setSettingsVisible(true) },
-      ]
-    );
-  };
-  // Settings unlock: a valid key persists PRO and returns true.
-  const handleUnlock = async (key: string): Promise<boolean> => {
-    const ok = await activatePro(key);
-    if (ok) {
-      setPro(true);
-      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
-    }
-    return ok;
+    Alert.alert('PRO FEATURE', `${feature} needs the PRO build.`);
   };
 
   // Watermark handed to the export engines (Skia + native): the ACCEPTED mark
@@ -1712,7 +1687,6 @@ export default function App() {
         startupMode={startupMode}
         onStartupMode={handleStartupMode}
         pro={pro}
-        onUnlock={handleUnlock}
       />
 
       {/* Session photo viewer (swipe across captured/exported photos) */}