docs(readme): comprehensively optimize README.md

Major improvements:
- Add visual table of contents for easy navigation
- Enhance header with more badges (Discussions, Python, CUDA)
- Add 'At a Glance' section with quick code example
- Improve installation section with troubleshooting guide
- Add comprehensive API reference table with signatures
- Expand performance comparison tables (memory + speed)
- Add ASCII architecture diagram for visual understanding
- Update project structure to reflect cuda_llm_ops/ directory
- Add pre-commit hooks section for development workflow
- Use collapsible details for examples to reduce length
- Enhance contribution guidelines with quick start steps
- Add bilingual documentation tables (EN/ZH)

README length: 307 → 550 lines (78% increase in content)
Navigation: Added TOC with 15+ anchor links
Visual: Added architecture diagram and improved tables

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

Author: shijiashuai