HEIC thumbnails: pull full file (partial reads unreliable for sips conversion)

1MB partial HEIC reads are not sufficient for sips to convert to JPEG.
Revert to full file pull for HEIC thumbnails. Files are cached permanently
so each HEIC is only transferred once — subsequent launches skip already-cached files.

src/main/resources/scripts/photophetch-ios-helper.py

@@ -176,15 +176,20 @@ async def cmd_batch_thumbs(pairs_json: str):
         for device_path, local_path in pairs:
             ext = device_path.rsplit('.', 1)[-1].lower() if '.' in device_path else ''
             is_heic = ext in ('heic', 'heif')
-            read_size = 1024 * 1024 if is_heic else 512 * 1024  # 1MB for HEIC, 512KB for others
             try:
                 os.makedirs(os.path.dirname(os.path.abspath(local_path)), exist_ok=True)
-                try:
-                    data = await afc.fread(device_path, read_size, 0)
-                    with open(local_path, 'wb') as f:
-                        f.write(data)
-                except Exception:
+                if is_heic:
+                    # HEIC: pull full file — sips needs the full image to convert to JPEG
+                    # Cached permanently so only transferred once
                     await afc.pull(device_path, local_path)
+                else:
+                    # JPEG/PNG: 512KB partial read is sufficient for sips resample
+                    try:
+                        data = await afc.fread(device_path, 512 * 1024, 0)
+                        with open(local_path, 'wb') as f:
+                            f.write(data)
+                    except Exception:
+                        await afc.pull(device_path, local_path)
                 results.append({'devicePath': device_path, 'ok': True})
             except Exception as e:
                 results.append({'devicePath': device_path, 'ok': False, 'error': str(e)})