Add renderer render pass clear contract

docs/modernization/roadmap.md

@@ -724,10 +724,11 @@ Results:
   validation, texture-upload byte-count validation, frame-capture byte-size and
   command-order validation, render-target blit validation, texture-slot binding
   validation, blend-state validation, scissor-state validation,
-  shader-uniform write validation, backend-neutral resource factory validation,
-  recording scissor/depth/blend/shader-uniform/texture/sampler-bind/upload/
-  readback/frame-capture/blit command capture, draw mesh-input capture, and
-  invalid catalog rejection.
+  render-pass color/depth/stencil clear validation, shader-uniform write
+  validation, backend-neutral resource factory validation, recording
+  render-pass clear/scissor/depth/blend/shader-uniform/texture/sampler-bind/
+  upload/readback/frame-capture/blit command capture, draw mesh-input capture,
+  and invalid catalog rejection.
 - `pp_paint_renderer_compositor_tests` passed.
 - `pp_ui_core_color_tests` passed.
 - `pp_ui_core_layout_value_tests` passed.
@@ -822,20 +823,21 @@ Results:
   implementation files.
 - `pp_renderer_api` now includes a headless `RecordingRenderDevice` with strict
   renderer-owned resource factory and
-  command-order/scissor-state/depth-state/blend-state/texture-bind/
-  sampler-bind/shader-uniform/texture-upload/readback/frame-capture/blit
-  validation; it creates validated textures, render targets, shaders, meshes,
-  and readback buffers, then records commands, trace markers, scissor state,
-  depth state, blend state, shader uniform writes, texture/sampler binds, draw
-  mesh inputs, uploads/readbacks, frame captures, and render-target blits,
-  giving automation a backend-neutral render path that does not require a
-  window or GL context.
+  command-order/render-pass-clear/scissor-state/depth-state/blend-state/
+  texture-bind/sampler-bind/shader-uniform/texture-upload/readback/
+  frame-capture/blit validation; it creates validated textures, render targets,
+  shaders, meshes, and readback buffers, then records commands, trace markers,
+  render-pass color/depth/stencil clear intent, scissor state, depth state,
+  blend state, shader uniform writes, texture/sampler binds, draw mesh inputs,
+  uploads/readbacks, frame captures, and render-target blits, giving automation
+  a backend-neutral render path that does not require a window or GL context.
 - `pano_cli record-render` exercises that headless recording renderer and emits
   JSON command counts, resource creation counts, target dimensions, backend
-  name, trace/draw summary, and draw vertex/index totals, scissor/depth/
-  blend-state plus shader-uniform/texture/sampler-bind/upload/readback/
-  frame-capture/blit command/byte totals for agent automation, with an
-  expected-failure smoke for oversized render/readback targets.
+  name, trace/draw summary, render-pass/depth-clear counts, and draw
+  vertex/index totals, scissor/depth/blend-state plus shader-uniform/texture/
+  sampler-bind/upload/readback/frame-capture/blit command/byte totals for
+  agent automation, with an expected-failure smoke for oversized
+  render/readback targets.
 - `pano_cli simulate-document-history` exercises pure document history
   apply/undo/redo behavior and emits JSON layer/frame/history state for agent
   automation.