Fix EXIF verification for non-Apple devices + sticky preserve folder

EXIF verification: any non-blank Make is now considered verified.
Only absent/empty Make triggers 'Origin unknown' warning. Samsung,
Google, etc. are all legitimate camera makes.
Also cache exifMake to avoid calling exiftool twice per file.

Preserve folder structure: add defaultPreserveFolderStructure to
AppConfig. Toggling in ImportScreen saves it as the new default.
prepareImport() reads from config instead of always resetting to true.

src/main/kotlin/com/bolenpad/photophetch/model/AppConfig.kt

@@ -17,6 +17,8 @@ data class AppConfig(
     val defaultStripLivePhotoMotion: Boolean = true,
     /** Default: do not delete from phone (safer default) */
     val defaultDeleteAfterVerify: Boolean = false,
+    /** Default: preserve folder structure on import */
+    val defaultPreserveFolderStructure: Boolean = true,
     /** Whether the user has been warned about HEIC phone settings */
     val heicWarningDismissed: Boolean = false,
     /** Path to adb binary, or null to use PATH */

src/main/kotlin/com/bolenpad/photophetch/transfer/Copier.kt

@@ -154,6 +154,8 @@ class Copier(
                 }
             }
 
+            val exifMake = readExifMake(finalFile)
+
             CopyResult(
                 photo = photo,
                 destinationPath = finalFile,
@@ -161,11 +163,8 @@ class Copier(
                 destSha256 = destHash,
                 verified = verified,
                 convertedFromHeic = wasConverted,
-                exifVerified = readExifMake(finalFile)?.let { make ->
-                    make.contains("apple", ignoreCase = true) ||
-                    make.contains(photo.exifMake ?: "apple", ignoreCase = true)
-                },
-                exifMake = readExifMake(finalFile),
+                exifVerified = exifMake?.let { it.isNotBlank() },
+                exifMake = exifMake,
                 error = when {
                     !verified && remoteHash != null -> "Hash mismatch — file may be corrupt"
                     !verified -> "Copy failed — file missing or size mismatch"

src/main/kotlin/com/bolenpad/photophetch/ui/AppState.kt

@@ -371,11 +371,11 @@ class AppState(private val configStore: ConfigStore) {
             StagingPath.uniqueFolderName(Paths.get(cfg.stagingRoot), baseName)
         } else baseName
 
-        // Multi-folder selection → preserve structure by default
+        // Multi-folder selection → preserve structure; otherwise use saved config default
         val multipleSourceFolders = _selectedPhotos.value.map { it.sourceFolder }.distinct().size > 1
         _importConfig.update { it.copy(
             folderName = folderName,
-            preserveFolderStructure = multipleSourceFolders,
+            preserveFolderStructure = if (multipleSourceFolders) true else cfg.defaultPreserveFolderStructure,
         ) }
         navigateTo(Screen.IMPORT_CONFIG)
     }
@@ -469,6 +469,11 @@ class AppState(private val configStore: ConfigStore) {
         saveConfig()
     }
 
+    fun updateDefaultPreserveFolderStructure(value: Boolean) {
+        _config.update { it.copy(defaultPreserveFolderStructure = value) }
+        saveConfig()
+    }
+
     fun dismissHeicWarning() {
         _config.update { it.copy(heicWarningDismissed = true) }
         saveConfig()

src/main/kotlin/com/bolenpad/photophetch/ui/ImportScreen.kt

@@ -154,7 +154,10 @@ fun ImportScreen(state: AppState) {
                 label = "Preserve folder structure",
                 description = "Files go into subfolders matching their source (Camera/, Screenshots/, etc.).",
                 checked = importConfig.preserveFolderStructure,
-                onCheckedChange = { state.updateImportConfig { copy(preserveFolderStructure = it) } },
+                onCheckedChange = {
+                    state.updateImportConfig { copy(preserveFolderStructure = it) }
+                    state.updateDefaultPreserveFolderStructure(it)
+                },
             )
             ToggleRow(
                 label = "Delete from phone after verification",