port: CMapOutdoor + PythonBackground + minimap (1:1 40250)

GameLib map/area/terrain units, PRTerrainLib Terrain/TextureSet,
PythonBackground(+Module) and ColorTransitionHelper ported verbatim;
pending stand-ins and background module stubs removed. Hand edits:
BeginEnvironment's pointer tag via uintptr_t, LoadWaterMap reads the
file's 32-bit longs. Terrain draw passes stay platform no-ops (Godot
draws the terrain). RecordingDevice gains textures, buffers and render
targets; orthographic draws become UI commands so CPythonMiniMap's
masked tiles show through minimap_image_filter in python_ui_surface.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

extension/src/platform/EterLib/UIRenderCommands.h

@@ -18,6 +18,10 @@ struct UIRenderCommand {
     float qx[4] = {}, qy[4] = {};
     float su = 0, sv = 0, eu = 1, ev = 1;
     int blend = 0; // CGraphicExpandedImageInstance::RENDERING_MODE_*
+    // A second texture stage that modulates the colour and replaces the alpha (40250 CPythonMiniMap's
+    // circular minimap_image_filter): the mask's texture coordinates at the quad's four corners.
+    std::string mask;
+    float mu[4] = {}, mv[4] = {};
 };
 
 // D3DXCOLOR (0..1 floats) -> the 0xAARRGGBB the commands carry.