style(ruff): minor cleanup for file open and import ordering

- Removed unnecessary `"r"` mode in open() call (default is already "r")
- Reordered imports to satisfy ruff's style rules

Author: BloggerBust

preswald/engine/transformers/reactive_runtime.py

@@ -79,7 +79,7 @@ def __init__(self, filename: str = "<script>"):
         self._used_display_renderer_fns: set[str] = set()
 
         try:
-            with open(filename, "r") as f:
+            with open(filename) as f:
                 self._source_lines = f.readlines()
         except Exception as e:
             logger.warning(f"[AST] Could not read source lines for file {filename}: {e}")

preswald/interfaces/render/error_registry.py

@@ -1,5 +1,6 @@
-from threading import Lock
 import os
+from threading import Lock
+
 
 """
 Provides a simple in-memory registry for collecting and retrieving structured