feat(ai-security-guard): implement AI logging for content security submissions

[JianweiWang]

Summary

• Add AI logging functionality for content security guard submissions, tracking requestId and submission events across all guard handlers
• New ai_log.go config and ai_log_test.go with comprehensive test coverage
• Updated handlers in text, image, and MCP moderation modules to integrate AI logging for both request and response phases
• README documentation updated to describe the new AI log event structure and behavior

Test plan

• Verify ai_log_test.go tests pass
• Test with guard handlers to confirm requestId is correctly logged on submission events

🤖 Generated with Claude Code

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✅ JianweiWang
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[codecov-commenter]

Codecov Report

❌ Patch coverage is 41.26394% with 158 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
...ity-guard/lvwang/multi_modal_guard/image/openai.go	16.00%	42 Missing ⚠️
...urity-guard/lvwang/multi_modal_guard/image/qwen.go	28.00%	36 Missing ⚠️
...security-guard/lvwang/multi_modal_guard/mcp/mcp.go	45.45%	24 Missing ⚠️
...rity-guard/lvwang/multi_modal_guard/text/openai.go	35.13%	24 Missing ⚠️
...ons/ai-security-guard/lvwang/common/text/openai.go	37.93%	18 Missing ⚠️
...y-guard/lvwang/text_moderation_plus/text/openai.go	33.33%	10 Missing ⚠️
...m-go/extensions/ai-security-guard/config/ai_log.go	90.90%	2 Missing and 2 partials ⚠️

📢 Thoughts on this report? Let us know!

[rinfx]

LGTM