Add YAML configuration example for Anthropic Claude #85

Description

The examples/ directory has a vLLM YAML config but no Anthropic YAML example. Adding one helps users who prefer config-driven pipelines with Claude models.

What to do

1. Create examples/claude_config.yaml based on the pattern in examples/12_vllm_custom.yaml
2. Set provider to anthropic, model to claude-sonnet-4-20250514
3. Include a sample prompt template and processing settings
4. Test that ondine process --config examples/claude_config.yaml --dry-run works

Acceptance criteria

• New YAML config file in examples/
• Dry-run executes without errors