Add synchronous job drain ability

[chubes4]

Summary

• Adds datamachine/drain-job, a synchronous Abilities API primitive for draining due Action Scheduler step work scoped to one job_id.
• Enforces both step and wall-clock budgets with defaults, reports terminal state/drain stats, and returns a typed error when the Action Scheduler runner is unavailable.
• Adds Playground/WP unit coverage for running a scheduled test flow to completed_no_items plus a pure-PHP smoke test for the ability contract.

Fixes #1803.

Approach

I chose option C from the issue because a separate datamachine/drain-job ability is the clean reusable primitive. Callers can compose datamachine/run-flow with datamachine/drain-job without adding caller-mode flags to the existing async flow execution path.

Testing

• php -l inc/Abilities/Engine/DrainJobAbility.php && php -l inc/Abilities/EngineAbilities.php && php -l tests/drain-job-ability-smoke.php && php -l tests/Unit/Abilities/Engine/DrainJobAbilityTest.php
• php tests/drain-job-ability-smoke.php
• vendor/bin/phpcs inc/Abilities/Engine/DrainJobAbility.php inc/Abilities/EngineAbilities.php tests/drain-job-ability-smoke.php tests/Unit/Abilities/Engine/DrainJobAbilityTest.php
• homeboy test data-machine -- --filter DrainJobAbilityTest still ran the full Playground PHPUnit suite instead of filtering.
• homeboy test data-machine -- tests/Unit/Abilities/Engine/DrainJobAbilityTest.php also ran the full Playground PHPUnit suite instead of selecting the file.

Full-suite result from those Homeboy runs: the new drain-job test passed, but the suite still has one unrelated failure: DataMachine\Tests\Unit\Abilities\ImageGenerationPromptRefinementTest::test_refine_prompt_includes_post_context_when_provided failing because the refined prompt is empty and does not contain Article context:.

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (gpt-5.5)
• Used for: Drafted the synchronous drain ability, registration wiring, and tests. Chris reviews, validates, and owns the final change.

[homeboy-ci]

Homeboy Results — data-machine

Lint

✅ lint — passed

ℹ️ Full options: homeboy docs commands/lint
Deep dive: homeboy lint data-machine --changed-since c0ef3b5

Test

✅ test — passed

• 1 passed

ℹ️ Auto-fix lint issues: homeboy refactor data-machine --from lint --write
ℹ️ Collect coverage: homeboy test data-machine --coverage
ℹ️ Save test baseline: homeboy test data-machine --baseline
ℹ️ Pass args to test runner: homeboy test -- [args]
ℹ️ Full options: homeboy docs commands/test
Deep dive: homeboy test data-machine --changed-since c0ef3b5

Audit

✅ audit — passed

• test_coverage — 2 finding(s)
• Abilities — 1 finding(s)
• Total: 3 finding(s)

Deep dive: homeboy audit data-machine --changed-since c0ef3b5

Tooling versions

• Homeboy CLI: homeboy 0.157.1+66bb6ecf
• Extension: wordpress from https://github.com/Extra-Chill/homeboy-extensions
• Extension revision: 221b9c8
• Action: Extra-Chill/homeboy-action@v2