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, 52 insertions, 33 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b06bd6d..fc4ea81 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,30 +6,22 @@ option(DEMO_SIZE_OPT "Enable size optimization flags" OFF)
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
-# Search in both debug and release
-set(WGPU_SEARCH_PATHS
-    ${CMAKE_CURRENT_SOURCE_DIR}/third_party/wgpu-native/target/debug
-    ${CMAKE_CURRENT_SOURCE_DIR}/third_party/wgpu-native/target/release
-)
-
-find_library(
-    WGPU_LIBRARY NAMES libwgpu_native.a wgpu_native.lib wgpu_native
-    HINTS ${WGPU_SEARCH_PATHS}
-    REQUIRED
-)
+# Find wgpu-native (system install)
+find_library(WGPU_LIBRARY NAMES wgpu_native libwgpu_native REQUIRED)
+find_path(WGPU_INCLUDE_DIR NAMES webgpu.h PATH_SUFFIXES webgpu-headers REQUIRED)
 
 include_directories(
     src
     third_party
-    third_party/wgpu-native/ffi
-    third_party/wgpu-native/ffi/webgpu-headers
+    ${WGPU_INCLUDE_DIR}
+    third_party/glfw3webgpu
 )
 
 find_package(glfw3 REQUIRED)
 
 set(DEMO_LIBS glfw ${WGPU_LIBRARY})
 
-# Platform-specific dependencies for wgpu-native
+# Platform-specific dependencies
 if (APPLE)
     set_source_files_properties(src/platform.cc PROPERTIES COMPILE_FLAGS "-x objective-c++")
     list(APPEND DEMO_LIBS
@@ -52,6 +44,7 @@ add_executable(demo64k
     src/audio/idct.cc
     src/audio/window.cc
     src/audio/synth.cc
+    third_party/glfw3webgpu/glfw3webgpu.c
 )
 
 target_link_libraries(demo64k PRIVATE ${DEMO_LIBS})
@@ -86,31 +79,57 @@ if(DEMO_BUILD_TESTS)
     target_include_directories(test_synth PRIVATE src)
     add_test(NAME SynthEngineTest COMMAND test_synth)
 
-    add_executable(test_spectool
-        src/tests/test_spectool.cc
-        src/audio/audio.cc
-        src/audio/window.cc
-        src/audio/fdct.cc
-        src/audio/synth.cc
-        src/audio/idct.cc
-    )
-    target_include_directories(test_spectool PRIVATE src third_party)
+        add_executable(test_spectool
+
+            src/tests/test_spectool.cc
+
+            src/audio/audio.cc
+
+            src/audio/window.cc
+
+            src/audio/fdct.cc
+
+            src/audio/synth.cc
+
+            src/audio/idct.cc
+
+            third_party/glfw3webgpu/glfw3webgpu.c
+
+        )
+
+        target_include_directories(test_spectool PRIVATE
+
+            src
+
+            third_party
+
+            ${WGPU_INCLUDE_DIR}
+
+            third_party/glfw3webgpu
+
+        )
     target_link_libraries(test_spectool PRIVATE ${DEMO_LIBS})
     add_test(NAME SpectoolEndToEndTest COMMAND test_spectool)
 endif()
 
 option(DEMO_BUILD_TOOLS "Build tools" OFF)
 if(DEMO_BUILD_TOOLS)
-    add_executable(spectool
-        tools/spectool.cc
-        src/platform.cc
-        src/audio/audio.cc
-        src/audio/fdct.cc
-        src/audio/idct.cc
-        src/audio/window.cc
-        src/audio/synth.cc
-    )
-    target_include_directories(spectool PRIVATE src third_party)
+        add_executable(spectool
+            tools/spectool.cc
+            src/platform.cc
+            src/audio/audio.cc
+            src/audio/fdct.cc
+            src/audio/idct.cc
+            src/audio/window.cc
+            src/audio/synth.cc
+            third_party/glfw3webgpu/glfw3webgpu.c
+        )
+        target_include_directories(spectool PRIVATE
+            src
+            third_party
+            ${WGPU_INCLUDE_DIR}
+            third_party/glfw3webgpu
+        )
     target_link_libraries(spectool PRIVATE ${DEMO_LIBS})
 
     add_executable(specview