widescreen: cinematic letterbox bars span the render width

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/game/addresses.h

@@ -148,4 +148,8 @@ constexpr uint32_t kGrannyOrthoPushSequences[] = {0x0040ebc9, 0x0040f5cf, 0x0040
 // push 1024: the height push, the width push follows 5 bytes later.
 constexpr uint32_t kLabelAreaPushes[] = {0x006272f8, 0x0060e940};
 
+// Cinematic letterbox bars (UI frame 0x7587b0): quads from x = 0 to 1024.0f,
+// stored as immediates.
+constexpr uint32_t kLetterboxRightImmediates[] = {0x0075895d, 0x007589f0, 0x00758aa5, 0x00758b29};
+
 } // namespace game::addr