[O01.01.12.05] Add a PublishAot smoke host to CI

[dotnetcadet]

Summary

Add a PublishAot smoke host to CI: a sample HRM graph on the reference test host that boots and answers a QUERY request over HTTP/1.1. HTTP/2/3 verification belongs to host adapters outside this repo per design decision D5. Blocked by G-07.

Acceptance Criteria

• A PublishAot smoke host boots and answers a QUERY request over HTTP/1.1 in CI.
• The host runs the sample HRM graph on the reference test host (V-07).
• CI fails if AOT publish or the smoke request fails.
• Tests cover the new behavior.
• The implementation remains NativeAOT-safe and trimming-safe.

Standards and Compliance

• Executes design decisions D3/D5: PublishAot smoke host on the reference host; blocked by G-07.