test: conversation runner smoke lacks current-user bootstrap stub

[chubes4]

Problem

Running the focused conversation-loop smoke test directly on current main fails its local tool execution assertion:

php tests/agent-conversation-runner-request-smoke.php

The executor returns executor_exception with:

Call to undefined function DataMachine\Abilities\get_current_user_id()

Evidence

The failure occurs in the pre-existing sandbox/pipeline local-tool case before this test reaches any changed external-runtime behavior. The pure-PHP bootstrap defines several WordPress function doubles but does not define get_current_user_id(), which the current ability execution path now reaches.

Expected

The standalone smoke test should provide the WordPress function surface required by the execution path and pass on a clean current-main checkout.

Reproduction

1. Check out current main at 271a9ff5f.
2. Run php tests/agent-conversation-runner-request-smoke.php.
3. Observe the failed sandbox/pipeline tool execution receives parsed parameters assertion and get_current_user_id() exception.

No production behavior is implicated; this is a standalone test-bootstrap regression.