feat(render): dynamic OpenGL/Vulkan backend split and backend-neutral viewer

- Extract libolive-rendercore static library to minimize backend link boundary.
- Add DynamicRenderer adapter with C ABI (oakgl/oakvulkan shared libs).
- Make OAK_ENABLE_DYNAMIC_RENDER_BACKEND default ON with OpenGL fallback.
- Implement VulkanRenderer prototype (textures, shaders, UBO blit, readback).
- Add backend-neutral viewer readback path (offscreen -> QImage -> QPainter).
- Refactor PluginRenderer to be renderer-agnostic; OFX plugins fall back to CPU
  path on non-OpenGL backends while preserving OpenGL render path.
- Add Renderer::AttachOutputTexture/DetachOutputTexture and C ABI forwards.
- Update docs/zh/render-backend-dynamic-plan.md for Phase 3/4/5.

app/widget/scope/scopebase/scopebase.cpp

@@ -22,6 +22,7 @@
 #include "scopebase.h"
 
 #include "config/config.h"
+#include "render/job/colortransformjob.h"
 
 namespace olive
 {
@@ -68,6 +69,11 @@ void ScopeBase::OnInit()
 
 void ScopeBase::OnPaint()
 {
+	if (IsBackendNeutral()) {
+		// TODO: implement backend-neutral scope display
+		return;
+	}
+
 	// Clear display surface
 	renderer()->ClearDestination();