Add LegacyDoc AI

[Dusangrm]

Description

Adds LegacyDoc AI to the IDE Extensions section.

LegacyDoc AI is a VS Code extension for developer workflows. It generates AI code audit reports, documentation, Mermaid architecture maps, and AI-ready codebase context from local workspaces.

Checklist

• The entry is a tool that uses AI
• The entry is a developer-focused tool
• The description is unambiguous and clear
• The description matches the style of other entries

[github-actions]

👋 Hi @Dusangrm,
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• Missing required section: ## Description
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