Add claude docs

.claude/display.md

@@ -0,0 +1,19 @@
+# Display System
+
+Source: `src/dusk/display/`
+
+## Overview
+
+The display system is a platform-abstracted rendering layer. Each
+subsystem (texture, shader, framebuffer, screen) is defined by a core
+header that requires the platform layer to provide concrete types and
+hook macros. The OpenGL implementation lives in `src/duskgl/`; the
+Dolphin (GX) implementation in `src/duskdolphin/`.
+
+## Subsystem documentation
+
+| Subsystem | Reference |
+|-----------|-----------|
+| Screen size modes, framebuffer, screen | `.claude/display-core.md` |
+| Texture, tileset, font | `.claude/display-texture.md` |
+| Shader, shader material, display state | `.claude/display-shader.md` |