Fix import hierarchy: Move debug_utils to core package (#175)

* Import modules not classes per Google style

Adds backward compat re-exports for API stability

* Refactor imports for better module compatibility

- Switch from lazy to direct registration in tests to avoid module path dependencies
- Update import style to use module imports instead of class imports
- Add compatibility checks for sandboxed build environments
- Fix debug_utils imports to work with flattened directory structures
- Add environment detection to skip incompatible tests in restricted contexts

This improves build system compatibility and makes the codebase more robust
across different deployment environments.

* Move debug_utils to core package to fix import hierarchy

Author: aksg87

langextract/__init__.py

@@ -66,7 +66,7 @@ def visualize(*args: Any, **kwargs: Any):
     "chunking": "langextract.chunking",
     "data": "langextract.data",
     "data_lib": "langextract.data_lib",
-    "debug_utils": "langextract.debug_utils",
+    "debug_utils": "langextract.core.debug_utils",
     "exceptions": "langextract.exceptions",
     "factory": "langextract.factory",
     "inference": "langextract.inference",

langextract/debug_utils.py renamed to langextract/core/debug_utils.py

@@ -28,7 +28,7 @@
 import enum
 import re
 
-from langextract import debug_utils
+from langextract.core import debug_utils
 from langextract.core import exceptions
 
 

langextract/core/tokenizer.py

@@ -148,7 +148,7 @@ def extract(
 
   if debug:
     # pylint: disable=import-outside-toplevel
-    from langextract import debug_utils
+    from langextract.core import debug_utils
 
     debug_utils.configure_debug_logging()