chore: Update version to 0.5.0 in project files and enhance version update script

update_version.py

@@ -31,20 +31,22 @@ def validate_version(version: str) -> bool:
     return bool(re.match(pattern, version))
 
 
-def update_file(file_path: Path, old_pattern: str, new_version: str) -> bool:
+def update_file(file_path: Path, old_pattern: str, new_version: str, multiline: bool = False) -> bool:
     """Update version in a file.
 
     Args:
         file_path: Path to file to update
         old_pattern: Regex pattern to find version
         new_version: New version string
+        multiline: Whether to use multiline mode for regex
 
     Returns:
         True if successful, False otherwise
     """
     try:
         content = file_path.read_text()
-        updated_content = re.sub(old_pattern, new_version, content)
+        flags = re.MULTILINE if multiline else 0
+        updated_content = re.sub(old_pattern, new_version, content, flags=flags)
 
         if content == updated_content:
             print(f"✓ {file_path.name} already up-to-date")
@@ -89,11 +91,13 @@ def main() -> int:
 
     # Update pyproject.toml
     if pyproject_path.exists():
-        pattern = r'version = "[^"]+"'
+        # Use word boundary to match 'version' but not 'python_version'
+        pattern = r'^version = "[^"]+"'
         success &= update_file(
             pyproject_path,
             pattern,
-            f'version = "{new_version}"'
+            f'version = "{new_version}"',
+            multiline=True
         )
     else:
         print(f"✗ {pyproject_path} not found")