feat(supported-version): add Mage-OS 3.0.0 (Magento 2.4.9) (#376)

* feat(supported-version): add Mage-OS 3.0.0 (Magento 2.4.9)

Add the mage-os/project-community-edition:3.0.0 entry (upstream
Magento 2.4.9) to individual.json and composite.json, and set the
previous 2.3.0 line to end-of-life on the 3.0.0 release date
(2026-05-19), per the same-day supersede convention.

3.0.0 adopts the Magento 2.4.9 certified service stack: MariaDB 11.4,
OpenSearch 3, RabbitMQ 4.1, Valkey 8 (replacing Redis), Varnish 7.7,
Nginx 1.28. PHP is set to 8.5 for the Mage-OS 3.0 line.

dist/index.js rebuilt; all 112 tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

* fix(supported-version): use PHP 8.4 for Mage-OS 3.0 line

Mirror the upstream Magento 2.4.9 certified row (php: 8.4) instead of
8.5, keeping the matrix aligned with magento-open-source. Updates the
3.0.0 individual entry and the composite >=3.0 <3.1 / open / :next
entries. dist/index.js rebuilt; 112 tests pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: marcelmtz