fix(core): preserve file service read contract

Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

src/basic_memory/services/file_service.py

@@ -308,13 +308,9 @@ async def read_file_bytes(self, path: FilePath) -> bytes:
                 )
                 return content
 
-        except FileNotFoundError:
-            # Preserve FileNotFoundError so callers (e.g. sync) can treat it as deletion.
-            logger.warning("File not found", operation="read_file_bytes", path=str(full_path))
-            raise
         except Exception as e:
             logger.exception("File read error", path=str(full_path), error=str(e))
-            raise FileOperationError(f"Failed to read file: {e}")
+            raise FileOperationError(f"Failed to read file: {e}") from e
 
     async def read_file(self, path: FilePath) -> Tuple[str, str]:
         """Read file and compute checksum using true async I/O.

src/basic_memory/sync/sync_service.py

@@ -39,7 +39,7 @@
 from basic_memory.repository.search_repository import create_search_repository
 from basic_memory.services import EntityService, FileService
 from basic_memory.repository.semantic_errors import SemanticDependenciesMissingError
-from basic_memory.services.exceptions import SyncFatalError
+from basic_memory.services.exceptions import FileOperationError, SyncFatalError
 from basic_memory.services.link_resolver import LinkResolver
 from basic_memory.services.search_service import SearchService
 
@@ -628,6 +628,14 @@ async def load(path: str) -> None:
                     )
                 except FileNotFoundError:
                     await self.handle_delete(path)
+                except FileOperationError as exc:
+                    # Trigger: FileService wraps binary read failures in FileOperationError.
+                    # Why: the service contract should stay consistent for direct callers.
+                    # Outcome: sync still treats wrapped missing-file reads as deletions.
+                    if isinstance(exc.__cause__, FileNotFoundError):
+                        await self.handle_delete(path)
+                    else:
+                        errors[path] = str(exc)
                 except Exception as exc:
                     errors[path] = str(exc)