fix: add missing __init__.py to prevent namespace package issue

Root cause:
- src/metaspec/ lacked __init__.py, causing Python to treat it as a namespace package
- metaspec.__file__ was None instead of pointing to the package location
- This caused CliRunner tests to fail while actual CLI worked fine

Impact:
- CliRunner couldn't properly load command metadata from typer.Option/Argument
- Tests failed with 'assert "--command" in result.stdout' even though options existed
- Actual installed CLI worked correctly because it loaded via entry points

Solution:
- Add src/metaspec/__init__.py with package metadata
- Now metaspec.__file__ points to /path/to/__init__.py (not None)
- CliRunner and actual CLI both load the same properly initialized package

Result:
✅ All 138 tests pass (4 previously failing tests now pass)
✅ metaspec is now a proper package, not a namespace package
✅ Consistent behavior between test environment and installed CLI

Author: NeilJo-GY

src/metaspec/__init__.py

@@ -0,0 +1,11 @@
+"""
+MetaSpec - Meta-specification framework for generating Spec-Driven X (SD-X) toolkits.
+
+A framework that generates complete, production-ready speck its (spec-driven toolkits)
+from YAML definitions.
+"""
+
+__version__ = "0.1.1"
+
+__all__ = ["__version__"]
+