Add render_dx09.cpp (selectable as `dx9ex` / `dx9`): renders the animated
pattern with Clear + ColorFill (D3D9's built-in rect fill -- no shaders) and
presents through a real D3D9 / D3D9Ex device. Two modes so the two D3D9 capture
paths each have a matching game. Smoke-verified: both present frames and exit
cleanly. The capture hook + frame-decode test land next.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
