lib.ExecContext.create(): Support path-only URIs

ExecContext.create() relies on properly formed URLs with a schema for
deciding which backend gets created. Create a Local instance if an
URL doesn't have schema.

Signed-off-by: Jan Lindemann <jan@janware.com>

src/python/jw/pkg/lib/ExecContext.py

@@ -289,9 +289,9 @@ class ExecContext(abc.ABC):
     @classmethod
     def create(cls, uri: str, *args, **kwargs) -> Self:
         tokens = re.split(r'://', uri)
-        schema = tokens[0]
+        schema = tokens[0] if tokens[0] != uri else 'file'
         match schema:
-            case 'local':
+            case 'local' | 'file':
                 from .ec.Local import Local
                 return Local(uri, *args, **kwargs)
             case 'ssh':