fix: ajustes de rutas y guards en vscode, rc y gpu_pipeline

- c_cpp_properties.json: añadir build/generated_shaders a includePath
- vibe3.rc: corregir ruta del icono a release/icons/icon.ico
- gpu_pipeline.cpp: envolver shaders MSL con guard #ifdef __APPLE__

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.vscode/c_cpp_properties.json

@@ -5,6 +5,7 @@
             "includePath": [
                 "${workspaceFolder}/source",
                 "${workspaceFolder}/source/external",
+                "${workspaceFolder}/build/generated_shaders",
                 "${env:HOMEBREW_PREFIX}/include",
                 "/opt/homebrew/include"
             ],
@@ -25,6 +26,7 @@
             "includePath": [
                 "${workspaceFolder}/source",
                 "${workspaceFolder}/source/external",
+                "${workspaceFolder}/build/generated_shaders",
                 "/usr/include",
                 "/usr/local/include"
             ],
@@ -41,6 +43,7 @@
             "includePath": [
                 "${workspaceFolder}/source",
                 "${workspaceFolder}/source/external",
+                "${workspaceFolder}/build/generated_shaders",
                 "C:/mingw/include"
             ],
             "defines": [