Zoom the FRAME preview instead of the photo, and save to DCIM/Camera

- FRAME tab now pinches the whole view (frame + photo + watermark) in both
  camera and library; one finger pans that view. Preview only: the exported
  file is identical at 1x and while the view is magnified.
- Watermark pinch/drag stay relative and keep priority while the WATERMARK
  row is open, so they still work after returning from the FRAME tab.
- Exports go through a native MediaStore insert into DCIM/Camera, falling
  back to expo-media-library when the native save fails.

modules/recipescam-export/android/src/main/java/com/locphamtran/recipescamera/export/RecipescamExportModule.kt

@@ -1,5 +1,6 @@
 package com.locphamtran.recipescamera.export
 
+import android.content.ContentValues
 import android.content.Context
 import android.graphics.Bitmap
 import android.graphics.BitmapFactory
@@ -10,6 +11,8 @@ import android.graphics.Paint
 import android.graphics.Rect
 import android.graphics.RectF
 import android.graphics.Typeface
+import android.os.Environment
+import android.provider.MediaStore
 import android.util.Base64
 import android.util.Log
 import expo.modules.kotlin.functions.Coroutine
@@ -74,6 +77,44 @@ class RecipescamExportModule : Module() {
     Name("RecipesCamExport")
     Log.i(TAG, "module defined RecipesCamExport")
 
+    // Save an encoded JPEG/PNG into DCIM/Camera. expo-media-library's JS API
+    // only ever inserts into DCIM (root) or Pictures/Camera, so a camera-roll
+    // export lands where the stock camera puts its shots by inserting the
+    // MediaStore row ourselves with an explicit RELATIVE_PATH. The file is
+    // staged IS_PENDING, copied from the cache path, then published. Returns the
+    // MediaStore _ID (same shape as expo's Asset.id, usable with
+    // deleteAssetsAsync), or "" when the insert/copy fails so JS can fall back.
+    AsyncFunction("saveToCameraRollAsync") Coroutine { srcPath: String, mimeType: String ->
+      val ctx = appContext.reactContext ?: error("react context lost")
+      withContext(Dispatchers.IO) {
+        val src = File(srcPath)
+        if (!src.exists()) return@withContext ""
+        val resolver = ctx.contentResolver
+        val values = ContentValues().apply {
+          put(MediaStore.MediaColumns.DISPLAY_NAME, src.name)
+          put(MediaStore.MediaColumns.MIME_TYPE, mimeType)
+          put(MediaStore.MediaColumns.RELATIVE_PATH, Environment.DIRECTORY_DCIM + "/Camera")
+          put(MediaStore.MediaColumns.IS_PENDING, 1)
+        }
+        val uri = try {
+          resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values)
+        } catch (e: Throwable) {
+          Log.w(TAG, "saveToCameraRollAsync insert failed: ${e.message}")
+          null
+        } ?: return@withContext ""
+        try {
+          resolver.openOutputStream(uri)?.use { out -> src.inputStream().use { it.copyTo(out) } }
+            ?: error("openOutputStream returned null")
+        } catch (e: Throwable) {
+          Log.w(TAG, "saveToCameraRollAsync copy failed: ${e.message}")
+          resolver.delete(uri, null, null)
+          return@withContext ""
+        }
+        resolver.update(uri, ContentValues().apply { put(MediaStore.MediaColumns.IS_PENDING, 0) }, null, null)
+        uri.lastPathSegment ?: ""
+      }
+    }
+
     // P0 spike: decode (BitmapFactory) + JPEG encode + file write, all off the
     // JS/main threads. Returns per-stage ms so JS can prove the JS thread is
     // never blocked while native rendering runs.

modules/recipescam-export/index.ts

@@ -91,6 +91,12 @@ export interface RecipescamExportModule {
   processPhotoAsync(srcPath: string, dstPath: string, matrix: number[], crop: CropRect | null, adjust?: PhotoAdjust): Promise<ColorTimings>;
   /** P1 alias: matrix + crop, no tone/cinema/enhance passes. */
   processColorAsync(srcPath: string, dstPath: string, matrix: number[], crop: CropRect | null, quality: number): Promise<ColorTimings>;
+  /**
+   * Insert an encoded image into DCIM/Camera (MediaStore RELATIVE_PATH) — where
+   * the stock camera writes. Returns the MediaStore _ID (expo Asset.id shape),
+   * or '' when the insert/copy fails, so JS falls back to MediaLibrary.
+   */
+  saveToCameraRollAsync(srcPath: string, mimeType: string): Promise<string>;
   /**
    * Raw device identity the stock Xiaomi camera folds into EXIF 0x889e (the
    * watermark blob HyperOS Gallery reads) but CameraX/HAL never supplies: