fix: resolve circular import and configure Python source directory

Configuration (pyproject.toml):
- Add [tool.setuptools] with package-dir = {"" = "python"}
- Add mypy_path = "python" to [tool.mypy]
- Tells IDEs that python/ is the source root (not python/rivet_di)

Circular Import Fix (python/rivet_di/decorators.py):
- Import Scope from rivet_di.scope module directly
- Avoids going through rivet_di.__init__.py during import
- Keeps type safety with Scope enum

The issue was that importing 'from rivet_di import Scope' triggers
__init__.py loading, but __init__.py also imports decorators, creating
a cycle. By importing from rivet_di.scope directly, we bypass __init__.py.

All behave tests passing (25/25 steps)

Author: mikelane

pyproject.toml

@@ -51,6 +51,9 @@ python-source = "python"
 module-name = "rivet_di._rivet_core"
 features = ["pyo3/extension-module"]
 
+[tool.setuptools]
+package-dir = {"" = "python"}
+
 [tool.pytest.ini_options]
 testpaths = ["tests"]
 python_files = ["test_*.py", "*_test.py"]
@@ -61,6 +64,7 @@ addopts = [
 
 [tool.mypy]
 python_version = "3.11"
+mypy_path = "python"
 warn_return_any = true
 warn_unused_configs = true
 disallow_untyped_defs = true

python/rivet_di/decorators.py

@@ -14,12 +14,13 @@ def component(
     Mark a class as a dependency injection component.
 
     Args:
-        scope: Lifecycle scope (SINGLETON or FACTORY)
+        scope: Lifecycle scope (SINGLETON or FACTORY), defaults to SINGLETON
 
     Returns:
         Decorated class with DI metadata
 
     Example:
+        >>> from rivet_di import Scope
         >>> @component(scope=Scope.SINGLETON)
         ... class DatabaseConnection:
         ...     pass