fix(llm): fix CN prompt output example format to match EN version

[linmengmeng-1314]

Summary

• Fix CN property graph extraction prompt output example: change from flat array [{...}, {...}] to structured format {"vertices":[...], "edges":[...]}
• Add missing "id" field in edge example to keep CN/EN consistent

Problem

The CN prompt (graph_extract_prompt_CN) used a flat array format for the output example, while:

• The EN prompt (graph_extract_prompt_EN) uses {"vertices":[...], "edges":[...]}
• The actual parsing logic in property_graph_extract.py expects the structured format

This mismatch could cause LLM to output incorrect JSON structure when processing Chinese text.

Test plan

• Verify ruff format and check pass
• Confirm CN output example now matches EN structure

🤖 Generated with Claude Code

[linmengmeng-1314]

Closing this PR — the upstream has already fixed the CN prompt output example format in commit 2df0b6e (PR #339). No further action needed.