[CLI] Run PHP in clean worker processes

[chubes4]

Fixes #4145.

What changed

• Adds runInFreshProcess() to Blueprint v1 and v2 CLI workers.
• Reuses the active CLI worker configuration, extensions, mounts, path aliases, and file-lock manager without booting WordPress into the new PHP runtime.
• Orders fresh executions within each worker without allowing a failed request to poison the queue.
• Executes code from worker-specific unique script paths instead of shared /internal/eval.php, preventing concurrent parse corruption.
• Disposes every temporary request handler and script after execution.

Why

Programmatic CLI consumers need project-owned bootstraps to start without PHP symbols inherited from the long-lived worker. The same API also needs to remain safe when several pooled CLI workers execute code concurrently.

Verification

• npx nx run playground-cli:typecheck
• npx nx run playground-cli:lint
• npx nx run playground-cli:test-playground-cli --testNamePattern="should run PHP without inheriting booted WordPress symbols"
• Downstream bounded PHPUnit parity workload: 680/680 suites passed under concurrency 64 with zero failures, timeouts, or cancellations.

AI assistance: OpenAI gpt-5.6-sol via OpenCode was used to review and implement the follow-up fixes and tests.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a runInFreshProcess() execution path for CLI workers so consumers can run PHP in a clean runtime (no inherited WP symbols), safely under worker concurrency, with per-run unique script paths and cleanup.

Changes:

• Introduces runInFreshProcess() for Blueprint v1/v2 worker threads with per-worker sequencing to avoid queue poisoning on failures.
• Executes code requests via unique temporary script paths and disposes the per-run request handler after execution.
• Adds an integration test validating WP symbols aren’t inherited across fresh runs while still allowing WP to be loaded when required.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
packages/playground/cli/tests/run-cli.spec.ts	Adds an integration test covering fresh-process execution isolation vs. booted worker state.
packages/playground/cli/src/blueprints-v2/worker-thread-v2.ts	Implements runInFreshProcess() with serialized execution, unique script paths, and cleanup.
packages/playground/cli/src/blueprints-v1/worker-thread-v1.ts	Implements runInFreshProcess() for v1, mirroring v2’s approach (with some config parity gaps).

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[chubes4]

@brandonpayton Review follow-up is ready: queue recovery now has explicit failure-then-success coverage in 3d89bb21f, all four review threads have responses, focused CLI typecheck/lint/integration tests pass, and a fresh CI run is underway. This API is the remaining upstream dependency for Automattic/wp-codebox#1938 and the downstream 680/680 PHPUnit parity result.

[chubes4]

Downstream full-stack validation completed against this PR plus #4108 using https://github.com/chubes4/wordpress-playground/tree/proof/bet12-clean-worker-abi.

• PHP 8.4 server-first TCP regression passes in a fresh process.
• WP Codebox bounded workers connect to a managed MariaDB service from the clean PHP process.
• Real focused WPCOM PHPUnit execution passed: 25 tests total across media-create integration and image/audio upload transport coverage.
• WP Codebox now rejects zero-exit runs without a non-zero PHPUnit summary, which caught the previous false-success behavior.

Downstream PR: Automattic/wp-codebox#1938