Release: Emulsify 7.x

[callinmullaney]

This PR does the following:

• Prepares Emulsify Drupal for the 7.x release line with Drupal ^11.3 || ^12 support.
• Removes the Stable9 base theme dependency and adds parent-owned template coverage for Drupal core template parity.
• Updates the Emulsify parent theme to use emulsify_tools:^2.0 and removes the direct drupal/components dependency.
• Updates Whisk to remain a hidden, generation-only starterkit source while generated child themes use emulsify as their runtime parent theme.
• Upgrades the generated Whisk starter theme to Emulsify Core ^4.0.0 and replaces Webpack references with the Vite-based build flow.
• Adds generated favicon package support to theme settings, including SVG upload, preview behavior, platform-specific browser/iOS/Android settings, manifest generation, and page-level head tag attachments.
• Adds favicon defaults, schema entries, admin preview CSS/JS, generation services, and smoke tests for package generation/portability.
• Refactors legacy hook includes into Drupal 11.3-style hook classes using #[Hook] attributes.
• Adds readiness tooling for render parity, no-Stable9 checks, starterkit generation, reference-page rendering, normalized HTML comparison, and release validation.
• Updates browser support config, npm package metadata, Husky setup, and semantic-release dependencies for the 7.0.0 release.

Related Issue(s)

• N/A

Notes:

• This is a major release PR.
• Drupal 10 support is removed.
• Whisk should not be enabled directly; it is only used as the starterkit source for generated themes.
• Favicon generation requires the PHP extensions needed to rasterize SVG assets, including Imagick and GD.

Functional Testing:

• Install this branch in a clean Drupal 11.3+ site.
• Confirm Composer resolves drupal/core:^11.3 || ^12 and drupal/emulsify_tools:^2.0.
• Enable the Emulsify theme and confirm the site renders without Stable9 as a base theme.
• Generate a child theme from Whisk and confirm the generated theme uses emulsify as its base theme.
• In the generated child theme, run npm install, npm run build, and npm run develop.
• Confirm Vite-generated assets are created and Storybook still starts successfully.
• Configure a generated favicon package from theme settings using an SVG source.
• Confirm favicon assets, manifest output, and related head tags are generated and attached to the page.
• Confirm the favicon preview UI updates in the theme settings form.
• Run the readiness/smoke scripts or GitHub Actions checks for template parity, no-Stable9 readiness, starterkit generation, and favicon generation.

Security

• SVG favicon uploads are sanitized before package generation.
• Unsafe SVG nodes, event handlers, and external references are stripped from the stored/generated favicon source.
• No other known security concerns.

Accessibility

• Parent-owned template coverage is intended to preserve Drupal core template behavior while removing the Stable9 runtime dependency.
• Favicon and build-tooling changes should be visually/semantically neutral.