Introduce renderer-driven and renderer-backed managed pipeline base types in the Universal package.
Move shared renderer-data/default-renderer ownership out of UniversalRenderPipelineAsset, migrate probe assets onto the generic seam, and expose renderer recording/request context types for future SRP expansion.
Update scripting API-surface expectations and validate with build, unit tests, scripting tests, and old editor smoke.
Invoke managed pipeline disposal and asset runtime cleanup from the native bridge lifecycle. Add Universal renderer and feature cleanup hooks plus regression probes to verify runtime cache teardown semantics.
