Add Mermaid extension recommendation for state machine documentation

[Copilot]

Adds VS Code workspace configuration to recommend the Mermaid extension for state machine diagram support.

Changes

• .vscode/extensions.json: Created with bierner.markdown-mermaid recommendation
• .vscode/settings.json: Added "extensions.ignoreRecommendations": false to enable recommendation prompts

When developers open this workspace, VS Code will prompt them to install the Mermaid extension for viewing and editing state machine diagrams in markdown.

Original prompt

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This section details on the original issue you should resolve

<issue_title>Add Mermaid Extension to recommend for state machine</issue_title>
<issue_description>Also add "extensions.ignoreRecommendations": false,
</issue_description>

<agent_instructions>Do all 3 issues in a single PR</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes Add Mermaid Extension to recommend for state machine #30

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