Enhance security by ensuring unique SSH host keys for VMs and protecting registry credentials. Update documentation to reflect changes in SSH key management and improve state file permissions.

uvm/state.py

@@ -94,6 +94,8 @@ class StateStore:
         if not path.exists():
             return State()
         try:
+            if path.stat().st_mode & 0o077:
+                os.chmod(path, 0o600)
             with path.open(encoding="utf-8") as state_file:
                 raw = json.load(state_file)
         except (OSError, json.JSONDecodeError) as error: