feat: add OPENAI_API_KEY to frontEnd module configuration

[vmlcode]

No description provided.

[Copilot]

Pull request overview

Adds an OPENAI_API_KEY application setting to the frontEnd App Service module so the frontend deployment can receive an OpenAI key via configuration.

Changes:

• Add OPENAI_API_KEY to the frontEnd module appSettings in infra/main.bicep.

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[Copilot]

This app setting uses mcpOpenAiApiKey directly, but the rest of the template consistently uses the normalized *Var value (e.g., mcpOpenAiApiKeyVar for OPENAI_API_KEY in the orchestrator settings). Using the *Var here would keep conventions consistent and avoids confusion given the parameter is described as "used by the MCP server" while it's now also consumed by the frontend; consider switching to mcpOpenAiApiKeyVar and/or clarifying the parameter naming/description to reflect shared use.

Suggested change

	value: mcpOpenAiApiKey
	value: mcpOpenAiApiKeyVar