[Compute Separation] Add standalone Host and WorkerProxy artifact smoke tests

[brettsam]

What problem would the feature you're requesting solve? Please describe.

The artifact-publishing work in #11986 and #12027 is deliberately limited to producing the standalone Linux Host and WorkerProxy artifacts. Automated process/container smoke coverage should be a separate follow-up rather than a BYOC-M1 publishing requirement.

The smoke tests should exercise the artifacts consumed by image builders, not rebuild the products through an unrelated path or treat a listener health response as proof that functions can execute.

Describe the solution you'd like

Add focused smoke coverage for the published Linux x64/Noble artifacts:

• Consume functions-host.linux-x64.tar.gz and worker-proxy.linux-x64.tar.gz, preserving executable permissions and using the documented entrypoints and runtime dependencies.
• Start the dedicated Azure.Functions.Host with zero workers and confirm its HTTP listener is healthy while distinguishing that from function invocation readiness.
• Start Native AOT Azure.Functions.WorkerProxy without a managed .NET runtime and confirm its management endpoint is available.
• For a linked HTTP smoke, launch one separately supplied .NET isolated test worker in the proxy's network namespace, configure the reachable proxy HTTP origin, link through PUT /admin/workers, then invoke the Host's sample HTTP function and assert the expected response.
• Require bounded startup, request, and shutdown waits. Send SIGTERM and verify clean process/container exits; retain useful logs on failure and clean up only test-owned resources.
• Keep test configuration and network exposure isolated. Verify existing supported behavior without adding new product configuration requirements, readiness APIs, or runtime behavior changes solely for the tests.

Acceptance criteria:

• Smoke tests run against the produced artifacts/images, with no alternate product publish path.
• Host/proxy listener health, actual linked-worker invocation, and graceful shutdown are reported as distinct outcomes.
• Failures produce actionable diagnostics, return a nonzero result, and do not leave test-owned processes or containers running.
• Existing standard Host behavior and its pipeline tests remain unchanged.

Scheduling: leave this issue without a milestone for now. Assign it to a future milestone when the smoke work is scheduled; it is not a blocker for #11986, #12027, or BYOC-M1 artifact publishing.

Out of scope: bundle-cache/fallback testing (covered elsewhere), a bespoke artifact-verifier framework, additional language/OS matrices, production authentication changes, registry publication, rollout/pool orchestration, or a bundled worker/supervisor product.

Describe alternatives you've considered

Keeping this coverage in the artifact-publishing PR was rejected to keep that change focused. Existing unit tests remain valuable, but they do not replace a future smoke against the actual published binaries and their container/runtime dependencies.

Additional context

• Split from [Compute Separation][PR-M10+HB4A] Publish the dedicated compute Host artifact #11986, [Compute Separation][PR-M10+HB4A] Publish the dedicated compute Host artifact.
• Artifact-publishing PR: adding new linux artifacts #12027.
• Related BYOC-M1 tracking issue: [Compute Separation] BYOC M1 one-worker HTTP vertical slice #11965; this follow-up is intentionally outside that milestone's artifact-publishing scope.
• The dedicated Host is framework-dependent .NET/ASP.NET Core 10; WorkerProxy is a self-contained Native AOT executable. The user worker remains external and shares the proxy's network namespace.