Promoted readonly properties can't be reassigned in the constructor
body, so GitLabProvider and GiteaProvider threw on every instantiation.
Normalize the plain parameter first, then assign to a separately
declared readonly property.
startFetch() resolves the user id and fires the first events page,
returning a handle without reading it; resolveFetch() continues the
existing do/while pagination starting from that first response.
Pagination itself stays sequential within this provider since each
page depends on the previous one - parallelism here only spans across
providers, not within GitLab's own pages.
Move all provider-related classes, enums, interface and trait into
App\Service\Provider; move SvgRenderer into App\Service\Renderer.
ContributionAggregator stays at the Service root as the orchestrator.
Test namespaces and use statements updated to match.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
haylan
