fix: guard autodelete for files referenced by multiple assets

When auto-delete tries to remove a file, check if other iCloud assets
still reference the same path in the manifest. If so, skip deletion
to prevent data loss during dedup migration.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: teh-hippo

src/icloudpd/autodelete.py

@@ -113,6 +113,15 @@ def autodelete_photos(
                 )
         for path in paths:
             if os.path.exists(path):
+                if manifest is not None and not path.endswith(".xmp"):
+                    rel_path = os.path.relpath(path, directory)
+                    # Guard: don't delete files shared by multiple assets
+                    if manifest.count_by_path(rel_path) > 1:
+                        logger.debug(
+                            "Keeping %s — other assets still reference it",
+                            path,
+                        )
+                        continue
                 logger.debug("Deleting %s...", path)
                 delete_local = delete_file_dry_run if dry_run else delete_file
                 if delete_local(logger, path) and manifest is not None and not path.endswith(".xmp"):