Real-WordPress PHP smoke harness needs a deterministic bootstrap contract

[chubes4]

Problem

The real-WordPress smoke execution environment can have WordPress functions loaded without the smoke being able to rely on the usual bootstrap markers. In Data Machine PR CI, a pure-PHP smoke guarded on defined( 'WPINC' ), but WP functions such as do_action() were already loaded, causing:

Cannot redeclare do_action() (previously declared in /wordpress/wp-includes/plugin.php)

This required changing the smoke to guard every stub with function_exists(). That is reasonable defensively, but the harness contract is ambiguous.

Expected

WP Codebox should document and/or enforce a deterministic contract for real-WordPress PHP smoke execution:

• whether WordPress is fully bootstrapped
• whether WPINC/ABSPATH are defined
• whether core functions are loaded
• whether pure-PHP smoke files should be skipped, isolated, or run in a non-WP process

Why

Ambiguous partial bootstrap makes standalone smoke tests brittle and creates CI-only failures that are hard to reproduce locally.

Evidence

Data Machine PR: Extra-Chill/data-machine#2638
Initial failure: tests/adjacent-handler-tool-policy-smoke.php redeclared do_action() under WP Codebox real-WP host smoke execution.