chore: enable mypy strict mode for maximum type safety

Added comprehensive mypy strict configuration:
- strict = true (enables all strict checks)
- disallow_untyped_calls = true
- disallow_untyped_decorators = true
- disallow_any_generics = true
- disallow_subclassing_any = true
- warn_unreachable = true
- strict_concatenate = true

Disabled overly restrictive checks:
- disallow_any_unimported = false
- disallow_any_expr = false
- disallow_any_decorated = false
- disallow_any_explicit = false

Updated overrides:
- Added rivet_di._rivet_core to ignore_missing_imports
- Kept behave.* for BDD testing framework

All existing code passes mypy strict mode (5 source files checked).
This ensures maximum type safety going forward.

Author: mikelane

pyproject.toml

@@ -65,19 +65,30 @@ addopts = [
 [tool.mypy]
 python_version = "3.11"
 mypy_path = "python"
+strict = true
 warn_return_any = true
 warn_unused_configs = true
 disallow_untyped_defs = true
 disallow_incomplete_defs = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_any_unimported = false
+disallow_any_expr = false
+disallow_any_decorated = false
+disallow_any_explicit = false
+disallow_any_generics = true
+disallow_subclassing_any = true
 check_untyped_defs = true
 no_implicit_optional = true
 warn_redundant_casts = true
 warn_unused_ignores = true
 warn_no_return = true
+warn_unreachable = true
 strict_equality = true
+strict_concatenate = true
 
 [[tool.mypy.overrides]]
-module = ["behave", "behave.*", "rivet_di"]
+module = ["behave", "behave.*", "rivet_di._rivet_core"]
 ignore_missing_imports = true
 
 [tool.ruff]