fix(symfony): separate route priority

[soyuka]

Summary

PR #8309 passed the existing operation priority to Symfony's route collection. That field controls operation ordering within a resource, so the change altered route matching for resources that rely on operation priorities.

This adds the distinct nullable routePriority metadata field, wires it through HTTP operations and YAML/XML metadata, and uses it when registering Symfony routes. Existing priority behavior is preserved.

CI analysis

The merged PR branch introduced route-ordering failures in the PostgreSQL, MySQL, MongoDB, Symfony 8.1, Symfony dev, PHP 8.2, event-listener, no-deprecations, and component matrix jobs. The failures included the prioritized-operation regression and route matches returning the wrong resource representation.

The remaining failed checks on the merged branch were pre-existing: api-platform/test dependency resolution in the minimal Symfony jobs, Unknown named parameter $detail in state/serializer jobs, and the dependent Codecov project check.

Test plan

• Focused ApiLoaderTest passes.
• PHPStan passes for changed source files.
• PHP CS Fixer passes.
• The broader functional matrix remains covered by CI.