Add disposable MySQL runtime service primitive

[chubes4]

Summary

• add a generic managed runtime-service schema with stable ids and explicit provider-output-to-runtime-env mappings
• provision disposable MySQL 8.4 through Docker on a loopback ephemeral port with tmpfs storage and protocol-level readiness before PHP-WASM starts
• integrate interruption-safe, timeout-safe, idempotent teardown and reviewer-safe persisted lifecycle evidence
• expose validation and dry-run plans, deterministic lifecycle/provider coverage, and a registered PHP-WASM mysqli E2E

Closes #1813.

Compatibility

This is additive for recipes that do not declare inputs.services. Existing recipe and runtime behavior remains unchanged. The schema stays provider-neutral at the recipe boundary; the initial mysql kind is implemented by Docker, and consumers explicitly choose their own environment variable names. No WPCOM-specific names, paths, or database naming policy are encoded.

Evidence

Source relationship: this implements the generic managed-service direction and acceptance criteria in #1813, informed by the linked downstream WPCOM contract and PHP-WASM MySQL readiness constraints.

Change kind: additive runtime-core contract, Docker MySQL provider, CLI orchestration/evidence integration, validation/dry-run surface, deterministic tests, and one registered live integration test.

Verification capability: deterministic tests use injected provider dependencies to prove protocol readiness behavior, loopback ephemeral publication, tmpfs/no persistent volume, credential redaction, Docker context preservation, environment collision validation, timeout/interruption cleanup, already-absent idempotency, and persisted cleanup evidence. The Docker-capable live E2E runs the public recipe lifecycle and PHP-WASM mysqli query.

Runtime scope: runtime changes are limited to recipes that explicitly declare managed services. The post-review hardening only closes demonstrated ownership gaps during timeout/interruption, preserves the selected Docker daemon context, and treats absence of an --rm container as successful teardown; it does not alter unrelated runtime functionality.

A Docker-capable Lab host already passed the live mysqli E2E and left zero wp-codebox containers. On the current non-Docker host, the registered package smoke reported its explicit Docker-unavailable skip while all deterministic coverage passed.

Fresh-Checkout Testing

1. git clone https://github.com/Automattic/wp-codebox.git
2. cd wp-codebox && git checkout feat/1813-disposable-mysql-service
3. npm ci
4. npm run build
5. npm run test:runtime-services
6. npm run test:runtime-services-lifecycle
7. npm run smoke -- --group package
8. On a Docker-capable host, run npm run test:disposable-mysql-mysqli-e2e.
9. Confirm teardown left no service containers with docker ps -a --filter name=wp-codebox --format "{{.ID}}"; the command must print nothing.

AI Assistance

OpenCode with OpenAI GPT-5.6 Sol assisted with review, focused implementation hardening, test coverage, rebase verification, and PR preparation.