Address code review feedback - final score 8.27/10

Co-authored-by: SomethingGeneric <12242178+SomethingGeneric@users.noreply.github.com>

Author: Copilot

miniupdate/os_detector.py

@@ -309,7 +309,6 @@ def _get_architecture(self, uname_info: Dict[str, str]) -> str:
                 return "arm"
             if arch.startswith("aarch64"):
                 return "arm64"
-            else:
-                return arch
+            return arch
 
         return "unknown"

miniupdate/vm_mapping.py

@@ -6,6 +6,7 @@
 
 import logging
 import os
+import sys
 from pathlib import Path
 from typing import Dict, Any, Optional, NamedTuple
 
@@ -125,7 +126,7 @@ def _load_mappings(self) -> Dict[str, VMMapping]:
 
         except Exception as e:
             logger.error("Failed to load VM mappings from %s: %s", self.mapping_path, e)
-            raise SystemExit(1) from e
+            sys.exit(1)
 
     def get_vm_info(self, host_name: str) -> Optional[VMMapping]:
         """Get VM mapping for a host."""