实现 AppleHandler 和 SamsungHandler 类，处理特定于供应商的 HEIC 特性，添加查找嵌入视频的逻辑

handlers/apple_handler.py

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+from .base_handler import VendorHandler
+
+class AppleHandler(VendorHandler):
+    """
+    Handles Apple-specific HEIC features.
+    Apple's motion photos (Live Photos) are stored in a separate MOV file,
+    so we won't find an embedded video here.
+    """
+    # We override the method to make it explicit that Apple files are handled,
+    # even though the result is the same as the base class.
+    def find_motion_photo_offset(self, heic_file) -> int | None:
+        # We could add logic here later to find the ContentIdentifier
+        print("Apple HEIC detected. Motion photo video is in a separate .mov file, not embedded.")
+        return None