Rlease: Prepare Emulsify Drupal 7.2 release readiness

[callinmullaney]

This PR does the following:

• Aligns repository, npm, generated Whisk starter, Composer, Drupal.org, and Packagist license metadata to GPL-2.0-or-later
• Updates LICENSE, package.json, package-lock.json, composer.json, and whisk/package.json so project license metadata is consistent
• Adds release guard coverage for license metadata, package metadata, Composer metadata, README documentation, release readiness docs, workflow expectations, and Whisk starter contracts
• Adds a sister-project parity contract documenting the shared Emulsify Drupal/WordPress product model and intentional Drupal-specific differences
• Normalizes docs and workflow language around the Whisk starter, generated child themes, parent theme behavior, Vite, Emulsify Core 4, and non-prefixed SemVer tags
• Expands Theme Readiness coverage with PHP 8.3, PHP 8.4, and advisory PHP 8.5 / Drupal dev-branch checks
• Modernizes CI to use actions/checkout@v7, actions/setup-node@v6, and node-version-file: .nvmrc
• Updates PHP linting to cover Drupal PHP-like files while pruning .git, node_modules, vendor, and whisk/node_modules
• Adds generated-source lineage metadata to Whisk with generatedFrom: "emulsify-drupal" and generatedFromVersion: "7.2.0"
• Updates Whisk to target @emulsify/core ^4.2.0
• Documents that Drupal intentionally keeps minimal Sass entrypoints because whisk.libraries.yml maps them to dist/global/*.css, while design-token tooling remains optional

Related Issue(s)

• N/A

Notes:

• This PR is focused on release readiness, metadata alignment, CI coverage, and documentation consistency for the 7.2 release.
• generatedFromVersion is intentionally set to 7.2.0 because this branch is preparing the next published Emulsify Drupal release.
• @emulsify/core is intentionally set to ^4.2.0 in anticipation of Core 4.2.0 being published before this branch merges.
• No Drupal theme PHP compatibility declaration is added; compatibility is validated through Theme Readiness CI instead.
• Full local release smoke coverage requires a Drupal fixture environment with GD and Imagick. Theme Readiness CI provides that coverage.

Functional Testing:

• Review LICENSE, package.json, package-lock.json, composer.json, and whisk/package.json to confirm project license metadata uses GPL-2.0-or-later.
• Run composer validate --no-check-publish --strict.
• Run npm ci --ignore-scripts.
• Run npm audit --omit=dev.
• Run npm audit.
• Run npm run lint:php.
• Run npm run docs:check-commands.
• Run npm run release:check -- --skip-smoke.
• Review .github/workflows/theme-readiness.yml to confirm Drupal 11.3 runs against PHP 8.3 and PHP 8.4, and Drupal dev-branch coverage runs against PHP 8.5 as advisory coverage.
• Review .github/workflows/theme-readiness.yml and .github/workflows/semantic-release.yml to confirm checkout/setup-node actions are updated and Node comes from .nvmrc.
• Review whisk/project.emulsify.json to confirm platform, singleDirectoryComponents, generatedFrom, and generatedFromVersion are preserved.
• After @emulsify/core@4.2.0 is published, run npm --prefix whisk install --package-lock=false --ignore-scripts.
• Run full npm run release:check in an environment with Drupal fixture prerequisites, GD, and Imagick available.