Fix archive PUTs missing Content-Type

[phattbeats]

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• I have read the contributing guideline and understand that I have made the correct modifications

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Description:

Default Content-Type to application/x-tar for Docker archive extraction PUT requests when the client omitted the header. Explicit client content types remain unchanged.

Benefits of this PR and context:

Docker's PUT /containers/{id}/archive endpoint can return HTTP 200 while extracting nothing when the request has no Content-Type. That creates a silent-success failure mode for callers sending a valid tar body. Supplying the endpoint's documented media type at the proxy keeps header-less clients from receiving a false success.

The rule is restricted to PUT requests whose decoded path exactly matches the versioned or unversioned container archive endpoint.

How Has This Been Tested?

Reproduced against Docker 24.0.9 through socket-proxy 3.4.2-r0-ls89:

• PUT of a valid tar without Content-Type: HTTP 200, subsequent archive GET returned 404.
• Identical PUT with Content-Type: application/x-tar: HTTP 200, subsequent archive GET returned 200.
• git diff --check passes.

A local HAProxy syntax check could not be run in the submitting environment because it lacks a Docker CLI and the deployed proxy denies container creation.

Source / References:

• Docker Engine API, Extract an archive of files or folders to a directory in a container: https://docs.docker.com/reference/api/engine/version/v1.43/#tag/Container/operation/ContainerArchive

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