feat(native-export): scaffold local Expo module + native decode/encode bench probe (P0)

Local Kotlin module modules/recipescam-export (autolinked via expo ./modules)
exposes decodeEncodeAsync — BitmapFactory decode -> JPEG q95 encode -> file,
all on Dispatchers.IO off the JS/main threads. EXPO_PUBLIC_BENCH=1 builds run
src/dev/nativeBenchProbe.ts: 3 timed decode+encode passes on the bundled
wallframe artwork plus a JS-timer gap check proving the JS thread never
blocks during native rendering. Legacy Skia engine untouched (reference).

App.tsx

@@ -139,6 +139,13 @@ export default function App() {
     // Do NOT auto-load device GPS here — it would override photo GPS on library mode
   }, []);
 
+  // P0 spike: native decode/encode benchmark (EXPO_PUBLIC_BENCH=1 builds only).
+  useEffect(() => {
+    if (process.env.EXPO_PUBLIC_BENCH === '1') {
+      import('./src/dev/nativeBenchProbe').then((m) => m.nativeBenchProbe());
+    }
+  }, []);
+
   // Save/restore session on app lifecycle changes
   useEffect(() => {
     const subscription = AppState.addEventListener('change', async (nextAppState) => {