fix(install): use Rocky Linux RHEL Docker repository

Add a Rocky-specific Docker install path to the stable and nightly install scripts, using Docker's documented RHEL repository flow. Include a unit test to lock in the Rocky repo selection and command set.

tests/Unit/InstallScriptRockyDockerRepoTest.php

@@ -0,0 +1,28 @@
+<?php
+
+function expectRockyInstallScriptToUseRhelRepo(string $path): void
+{
+    $installScript = file_get_contents(base_path($path));
+
+    expect($installScript)
+        ->toContain('install_docker_from_rhel_repo() {')
+        ->toContain('echo " - Installing Docker from the RHEL repository for Rocky Linux..."')
+        ->toContain('rm -f /etc/yum.repos.d/docker-ce.repo /etc/yum.repos.d/docker-ce-staging.repo')
+        ->toContain('dnf config-manager --add-repo https://download.docker.com/linux/rhel/docker-ce.repo')
+        ->toContain('dnf install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin')
+        ->toContain('systemctl --now enable docker')
+        ->toContain('"rocky")')
+        ->toContain('install_docker_from_rhel_repo')
+        ->not->toContain('dnf -y -q --setopt=install_weak_deps=False install dnf-plugins-core')
+        ->not->toContain('dnf5 config-manager addrepo --overwrite --save-filename=docker-ce.repo --from-repofile=https://download.docker.com/linux/rhel/docker-ce.repo')
+        ->not->toContain('dnf makecache')
+        ->not->toContain('"ubuntu" | "debian" | "raspbian" | "centos" | "fedora" | "rhel" | "rocky" | "sles")');
+}
+
+it('uses the rocky linux documented docker install flow in the stable install script', function () {
+    expectRockyInstallScriptToUseRhelRepo('scripts/install.sh');
+});
+
+it('uses the rocky linux documented docker install flow in the nightly install script', function () {
+    expectRockyInstallScriptToUseRhelRepo('other/nightly/install.sh');
+});