Add Makefile for hello_python example with development workflow targets:
- venv: Create virtual environment with SDK and dependencies
- install: Install/update dependencies in existing venv
- dist: Package plugin as tar.gz with vendored SDK
- dist-minimal: Package plugin without SDK (server must have SDK)
- clean: Remove build artifacts
- run: Run plugin locally for testing
- lint: Run type checking on plugin code
- help: Show available targets and development workflow
This Makefile serves as a template for Python plugin developers.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
