Add support for ApiKey auth to rust-server

[dsteeley]

Add ApiKey auth support to rust-server. This adds support to the client side and fixes the broken server side ApiKey support.

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Summary by cubic

Add ApiKey authentication to the rust-server and its generated client. The CLI can pass an API key, the client sends it in the header, and the server now reads it correctly.

• New Features

  • CLI support: --api-key and ENV VAR <CRATE_NAME>_API_KEY.
  • Client adds the ApiKey as a header using the security scheme’s keyParamName.

• Bug Fixes

  • Server extracts the ApiKey from request headers using the security scheme’s keyParamName (lowercased), restoring header-based ApiKey auth.
  • Removed reliance on a vendor extension for the header name.

^{Written for commit ff7f5d1. Summary will update on new commits.}

[cubic-dev-ai]

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