Prepare for Matomo 6

[sgiehl]

Description

Prepares the plugin for Matomo 6.

• plugin.json: version 5.0.1 → 6.0.0, and require.matomo → >=6.0.0-b1,<7.0.0-b1. The -b1
  lower bound is required so the plugin is not disabled against a beta core.
• CHANGELOG.md: new 6.0.0 entry.
• .github/workflows/phpcs.yml: the PHPCS job ran on PHP 7.4, which is below Matomo 6's PHP 8.1 floor.
  Bumped to 8.1. This workflow calls setup-php directly, so it does not go through the central
  matomo6_* alias resolver.

No code changes were needed. The Matomo 6 breaking-changes catalogue was swept against this repository —
removed PHP APIs, removed HTTP API methods, removed global functions, changed interfaces, the
Monolog 3 / PHP-DI 7 / Symfony 6.4 / php-tracker 4 dependency upgrades, the #[JsonResponse] controller
contract, removed Less variables and stylesheets, removed JS/Vue APIs, and the Jest → Vitest migration —
with no hits. Both integration points were checked against core 6.x directly: the
Tracker.getJavascriptCode event and the $codeImpl['protocol'] key it writes are unchanged in
core/Tracker/TrackerCodeGenerator.php, and Piwik\DI::decorate() still exists with the same decorator
signature under PHP-DI 7.

The plugin declares no composer.json, Updates/, vue/src, phpstan.neon or test workflows, so the
corresponding preparation steps do not apply.

Both commits are marked [ignore_release]: this only establishes Matomo 6 compatibility and nothing can
be released for Matomo 6 until core ships.

Issue No

Related to the Matomo 6 plugin preparation effort.

Steps to Replicate the Issue

1. Mount the plugin into a Matomo 6 checkout (PHP 8.1, MySQL 8.0, Node 24) and activate it —
   ./console plugin:activate ForceSSL succeeds.
2. ./console core:update reports no pending migrations.
3. ./console config:get --section=General --key=force_ssl returns "1", confirming the config
   decorator still applies on Matomo 6.
4. ./vendor/bin/phpcs --standard=phpcs.xml passes on PHP 8.1.

Checklist

• [✔] Tested locally or on demo2/demo3?
• [NA] New test case added/updated?
• [NA] Are all newly added texts included via translation?
• [NA] Are text sanitized properly? (Eg use of v-text v/s v-html for vue)
• [✔] Version bumped?
• [✔] I have understood, reviewed, and tested all AI outputs before use
• [✔] All AI instructions respect security, IP, and privacy rules
• [NA] Documentation updated?