Sell PRO as an in-app unlock, take shared photos, and let FX run negative

- One free Play app (com.locphamtran.recipescamera) with an expo-iap PRO
  unlock, replacing the paid apk for the store channel
- Android SEND/SEND_MULTIPLE share target feeds photos into the editor,
  on cold start and on resume
- BACK button in the TopBar and press-and-hold PEEK replace the chip row
- NOISE REDUCTION and SHARPENING accept -10: a negative SHARPENING softens
  the frame before the grain pass, a negative NOISE REDUCTION re-grains it,
  in the Skia engine, the live preview and the Kotlin export path alike

src/utils/nativeExport.ts

@@ -73,10 +73,11 @@ export async function processAndExportPhotoNative(
     // (EXPO_PUBLIC_NATIVE_EXPORT is not inlined into a release HBC bundle).
     const tone = getToneUniforms(adjustments, recipe.baseFilter);
     const cinema = getCinemaUniforms(recipe.cinema);
-    // Final screen sharpen (engine #9): the sharpening knob (0..10) overrides
+    // Final screen sharpen (engine #9): the sharpening knob (-10..10) overrides
     // the legacy boolean sharpen flag (camera captures keep it true → 0.5).
     const sharpKnob = adjustments.sharpening ?? 0;
-    const sharpenAmount = sharpKnob > 0 ? (sharpKnob / 10) * 0.8 : options?.sharpen ? 0.5 : 0;
+    const sharpenAmount =
+      sharpKnob > 0 ? (sharpKnob / 10) * 0.8 : sharpKnob < 0 ? 0 : options?.sharpen ? 0.5 : 0;
     const aspect: '4:3' | '3:2' | undefined =
       options?.aspect && options.aspect !== 'full' && frameId !== 'wallframe'
         ? options.aspect
@@ -99,6 +100,8 @@ export async function processAndExportPhotoNative(
           ? { locality: gpsInfo.locality || 'STREET VIEW', timestamp: gpsInfo.timestamp }
           : null,
       sharpen: sharpenAmount > 0 ? sharpenAmount : undefined,
+      // Negative knob -> Kotlin soften blur, pre-grain (engine step 4).
+      soften: sharpKnob < 0 ? (Math.abs(sharpKnob) / 10) * 3 : undefined,
       dpi: options?.dpi && options.dpi > 0 ? options.dpi : undefined,
       aspect,
     };