Complete native Joomla MCP console plugin and installed verification

[Llewellynvdm]

Why

Expose the PHP MCP component through Joomla's genuine console lifecycle while keeping the component responsible for catalogue, authorization, JCB handlers, jobs and recovery.

Implemented

• Lazy native adapters for serve, describe, dispatch, self-test, cli-inventory and jcb-sync.
• Console-only authority, native global options, atomic registration, exact input/exit handling and protocol-output restoration.
• Reproducible PHP-only Joomla ZIP, dependency/version checks, native installer/update behavior and gated release metadata.
• Eighteen installed CLI/stdio assertions, including exact/oversized JSON and NDJSON frame boundaries.

Validation

• Final PHP 8.3/8.4 native, package and release checks
• Final installed Joomla console acceptance
• Coordinated component/JCB checklist, including the four-platform core matrix and real JCB compiler/package/jobs through local and remote tracks.

Runtime code stays thin; no duplicated JCB catalogue or external-client dependency. Related component PR and client PR.

No merge or release publication is performed by this PR.