refactor: remove outdated __version__ from hatch/__init__.py

Remove hardcoded version string (__version__ = '0.4.0') from hatch/__init__.py.

This eliminates version duplication and establishes pyproject.toml as the single
source of truth for version information. Version will now be retrieved dynamically
via importlib.metadata.version('hatch').

Breaking change: Code that relied on hatch.__version__ will need to use
importlib.metadata.version('hatch') instead.

Related to: Phase 1 analysis (version_command_analysis_v1.md)

Author: LittleCoinCoin

hatch/__init__.py

@@ -5,8 +5,6 @@
 and interacting with the Hatch registry.
 """
 
-__version__ = "0.4.0"
-
 from .cli_hatch import main
 from .environment_manager import HatchEnvironmentManager
 from .package_loader import HatchPackageLoader, PackageLoaderError