refactor(gpu): Integrate WebGPU via system wgpu-native and glfw3webgpu

Replaces the complex wgpu-native submodule and manual platform-specific surface creation with a system-wide wgpu-native install (via Homebrew) and the glfw3webgpu helper library.

- Updates scripts/project_init.sh to fetch glfw3webgpu and ensure wgpu-native is installed.

- Refactors CMakeLists.txt to link against the system wgpu-native library.

- Simplifies src/platform.cc to use glfwCreateWindowWGPUSurface.

- Simplifies src/gpu/gpu.cc to use standard WebGPU headers.

- Updates FETCH_DEPS.md with new installation instructions.

- Updates PROJECT_CONTEXT.md with the new integration strategy.

1 files changed, 16 insertions, 9 deletions

diff --git a/scripts/project_init.sh b/scripts/project_init.sh
index db24c8f..549e146 100755
--- a/scripts/project_init.sh
+++ b/scripts/project_init.sh
@@ -14,19 +14,26 @@ else
   echo "miniaudio.h already present."
 fi
 
-# wgpu-native submodule
-if [ ! -d third_party/wgpu-native ]; then
-  echo "Fetching wgpu-native submodule..."
-  git submodule update --init --recursive
+# glfw3webgpu (helper for GLFW + WebGPU)
+mkdir -p third_party/glfw3webgpu
+if [ ! -f third_party/glfw3webgpu/glfw3webgpu.h ]; then
+  echo "Fetching glfw3webgpu..."
+  curl -L https://raw.githubusercontent.com/eliemichel/glfw3webgpu/main/glfw3webgpu.h -o third_party/glfw3webgpu/glfw3webgpu.h
+  curl -L https://raw.githubusercontent.com/eliemichel/glfw3webgpu/main/glfw3webgpu.c -o third_party/glfw3webgpu/glfw3webgpu.c
 else
-  echo "wgpu-native submodule already present."
+  echo "glfw3webgpu already present."
 fi
 
-if [ ! -f third_party/wgpu-native/target/release/libwgpu_native.a ]; then
-  echo "Building wgpu-native static library..."
-  (cd third_party/wgpu-native && make lib-native)
+# Check for wgpu-native (system install)
+if command -v brew >/dev/null 2>&1; then
+  if ! brew list wgpu-native >/dev/null 2>&1; then
+    echo "Warning: wgpu-native not found via brew. Installing..."
+    brew install wgpu-native
+  else
+    echo "wgpu-native found (via brew)."
+  fi
 else
-  echo "wgpu-native static library already built."
+  echo "Warning: Homebrew not found. Ensure wgpu-native is installed manually."
 fi
 
 echo "Done."