Add renderer and package readiness validation gates

docs/modernization/roadmap.md

@@ -1836,7 +1836,7 @@ Gate:
 
 Goal: prepare Vulkan and Metal without destabilizing the OpenGL parity path.
 
-Status: not started. Do not start production Vulkan or Metal work until
+Status: in progress. Do not start production Vulkan or Metal work until
 `RND-007` and `RND-008` freeze and validate the renderer API backend contract.
 `RND-009` and `RND-010` are opt-in lab targets only and must stay outside the
 production app path.
@@ -1848,6 +1848,14 @@ Implementation tasks:
   - `pp_renderer_metal_lab`
 - Use `D:\Dev\vkpaint` as reference material for Vulkan painting experiments,
   not as direct production code.
+- Record and enforce the renderer API contract surface in
+  `docs/modernization/renderer_api_contract.md` and keep
+  `panopainter_renderer_api_contract_self_test` as a precondition for
+  `RND-007` closeout.
+- Add and keep a renderer-conformance matrix fixture profile using
+  `renderer-conformance` labels plus `ctest --preset renderer-conformance` and
+  `ctest --preset desktop-gpu`, enforced by
+  `panopainter_renderer_conformance_matrix_self_test` before `RND-008` closeout.
 - Before integration, prove:
   - ping-pong compositing path
   - input-attachment/subpass path where applicable