Expose native camera frame planning controls to managed pipeline assets and renderer features.
Allow managed planning to override fullscreen stage heuristics while keeping CameraFramePlan as the native execution contract.
Add scripting coverage, probe assets, and archive the phase plan after build, test, and editor smoke validation.
- 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
