Add CLI smoke test for hc-agent demo

[binrogithub]

Motivation

• Provide a smoke test to exercise the hc-agent run demo --mode preview CLI path and surface regressions in CLI wiring.
• Prevent accidental network I/O during the test by ensuring HTTP calls would fail if attempted.

Description

• Add tests/test_cli_smoke.py which loads the hc-agent console script via entry points and invokes it with click.testing.CliRunner.
• Patch requests.request to raise an AssertionError if called to ensure no network requests occur during the test.
• Assert that the command exits with exit_code == 0, that output contains a run_id or a summary, and if a run_id is found then runs/<run_id>/report.md exists.

Testing

• No automated test suite was executed as part of this change (tests were added but not run).

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Codex Task