Scale software delivery without owning the runner fleet

Introduces 'Hosted Runners for GitLab Dedicated' as a fully managed CI execution SaaS offering. This feature eliminates the need for customers to manage their own runner fleet, abstracting provisioning, patching, and scaling. Key benefits include job-level security via isolated VMs, autoscaling for bursty CI demands, high reliability (99.9% SLA), and consumption-based pricing using GitLab Credits. It supports compliance through full isolation and single-tenant runners, and network security via AWS PrivateLink. This is an add-on to GitLab Dedicated.