fix(macos): compile the VideoToolbox import and clean platform warnings

The macOS job finally reached the build (after the vcpkg manifest fix) and
hit a macOS-only compile error in the VideoToolbox import: `*ptr as
*const T` parses as `(*ptr) as *const T`, so `sw_format` was read off a
pointer instead of the AVHWFramesContext. Bind the frames pointer first.

Also fix the warnings the cross-check surfaced: the redundant
MTLPixelFormat import, and doc comments on an extern block and a
thread_local! (rustdoc does not document those).

Verified locally with a host-cc wrapper:
`cargo check -p oak-core -p oak-codec -p oak-node -p oak-render
-p oak-task -p oak-plugin --target aarch64-apple-darwin` is clean.
(oak-app itself needs a real Apple toolchain for ring.)

crates/oak-codec/src/gpuinterop.rs

@@ -516,7 +516,7 @@ fn d3d11_import(req: &HwImportRequest<'_>, ctx: &Arc<GpuContext>) -> ImportOutco
 // macOS: VideoToolbox CVPixelBuffer -> IOSurface -> Metal textures
 // ---------------------------------------------------------------------------
 
-/// `CVPixelBufferGetIOSurface` (CoreVideo).
+// `CVPixelBufferGetIOSurface` (CoreVideo).
 #[cfg(target_os = "macos")]
 #[link(name = "CoreVideo", kind = "framework")]
 extern "C" {
@@ -543,7 +543,8 @@ fn videotoolbox_import(req: &HwImportRequest<'_>, ctx: &Arc<GpuContext>) -> Impo
 		return ImportOutcome::Unsupported;
 	}
 	// SAFETY: `hw_frames_ctx` is an AVHWFramesContext for this frame.
-	let sw_format = unsafe { (*(*frames).data as *const sys::AVHWFramesContext).sw_format };
+	let hw_frames = unsafe { (*frames).data as *const sys::AVHWFramesContext };
+	let sw_format = unsafe { (*hw_frames).sw_format };
 	let format = match sw_format {
 		sys::AVPixelFormat::AV_PIX_FMT_NV12 => PlanarFormat::Nv12,
 		sys::AVPixelFormat::AV_PIX_FMT_P010LE | sys::AVPixelFormat::AV_PIX_FMT_P010BE => {

crates/oak-core/src/backend/external.rs

@@ -459,8 +459,7 @@ impl GpuContext {
 		use objc2::runtime::ProtocolObject;
 		use objc2_io_surface::IOSurfaceRef;
 		use objc2_metal::{
-			MTLDevice as _, MTLPixelFormat, MTLStorageMode, MTLTextureDescriptor,
-			MTLTextureType, MTLTextureUsage,
+			MTLDevice as _, MTLStorageMode, MTLTextureDescriptor, MTLTextureType, MTLTextureUsage,
 		};
 		use wgpu::hal;
 

crates/oak-plugin/src/gl_bridge.rs

@@ -252,13 +252,13 @@ mod imp {
 	const K_CGL_PFA_COLOR_SIZE: i32 = 8;
 	const K_CGL_PFA_ALPHA_SIZE: i32 = 11;
 
-	/// macOS：CGL + OpenGL 的 FFI 声明（直接链接 OpenGL.framework）。
-	///
-	/// # Safety
-	///
-	/// 全部是系统 framework 导出函数；指针参数语义见各函数注释。
-	/// CGL* 类型用 `*mut c_void` 表示不透明对象指针（CGLContextObj /
-	/// CGLPixelFormatObj）。
+	// macOS：CGL + OpenGL 的 FFI 声明（直接链接 OpenGL.framework）。
+	//
+	// # Safety
+	//
+	// 全部是系统 framework 导出函数；指针参数语义见各函数注释。
+	// CGL* 类型用 `*mut c_void` 表示不透明对象指针（CGLContextObj /
+	// CGLPixelFormatObj）。
 	#[link(name = "OpenGL", kind = "framework")]
 	unsafe extern "C" {
 		/// 按属性列表选像素格式（成功返回 kCGLNoError=0；`npix` 是
@@ -406,8 +406,8 @@ mod imp {
 		_ctx: Arc<GlContext>,
 	}
 
-	/// 当前线程的 acquire 嵌套深度。>0 = 本线程已持外层 guard（上下文
-	/// 已 current）；嵌套 acquire 只递增深度，不重取锁。
+	// 当前线程的 acquire 嵌套深度。>0 = 本线程已持外层 guard（上下文
+	// 已 current）；嵌套 acquire 只递增深度，不重取锁。
 	thread_local! {
 		static ACQUIRE_DEPTH: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
 	}