Major developer experience upgrade - CLI commands, embeddings, validation

• Add 'mocktopus init' command with 5 comprehensive templates (basic, rag, agents, multimodal, enterprise)
• Add 'mocktopus doctor' command for environment and configuration diagnosis
• Add 'mocktopus explain' command for step-by-step rule matching debugging
• Implement full embeddings API endpoint (/v1/embeddings) with mock/record/replay support
• Add comprehensive JSON schema validation with fallback for scenarios
• Enhanced 'mocktopus validate' with logical checks and detailed reporting
• Professional developer experience matching industry standards

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: haasonsaas