Renderer screenshot hook unavailable

RuntimeHooks::screenshot has no renderer integration. Screenshot requests fail; headless desktop export verification also reports this as a warning while its conformance checks can still pass.

#Common causes

• The runtime uses the default hook or a headless conformance template without renderer capture.

#Fixes

• Implement RuntimeHooks::screenshot using ara-render capture at a safe frame boundary and return PNG bytes.

• For a headless verification run, treat the report as runtime-conformance evidence without a rendered screenshot.

• Code: ARA-EXP-BRG-010 (slot 8086)

• Constant: bridge::BRG_010

• Reported by: ara-bridge