Release v2.0.3

fix: Remove dotenv.config() from library classes

Libraries should not call dotenv.config() — that's the application's
responsibility. With dotenv v17, .config() writes to stdout, which
breaks MCP servers and other stdio-based protocols that use this library.

Removed from AutotaskClient, EnhancedAutotaskClient, and the client
generator template. The CLI entry point retains its dotenv usage since
it is an application, not a library.

Bumps version to 2.0.3.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>