Promote ScriptableRenderer renderer-recording context methods to the primary Universal execution seam and route the renderer-driven pipeline through that seam.
Update managed probes and scripting expectations to cover the new non-public renderer recording contract, and archive the completed phase plan.
- derive fullscreen stage planning from pipeline render-graph support
- trim planning-only APIs from the managed SRP bridge and public surface
- update probes and tests to lock the slimmer SRP API boundary
