fix: Register StorageBuffer for WebGPU device lose/restore

[mvaligursky]

WebGPU device loss previously either crashed when iterating GraphicsDevice.buffers (if StorageBuffer was tracked without loseContext/unlock) or skipped storage buffers entirely, leaving stale GPUBuffer references after requestDevice(). This change registers storage buffers on the device and runs the same lose/restore path as other buffers.

Changes:

• Add StorageBuffer to GraphicsDevice.buffers on construction; remove on destroy().
• Implement StorageBuffer loseContext() / restoreContext() (GPU backing recreated at the same byte size; contents are undefined until rewritten or recomputed). Document that in the class JSDoc.
• GraphicsDevice.restoreContext() calls buffer.restoreContext() instead of unlock().
• VertexBuffer and IndexBuffer add @ignore restoreContext() delegating to unlock() so the public lock/unlock API is unchanged.
• WebgpuBuffer: loseContext() clears the buffer reference only (aligned with WebglBuffer); allocate() applies the GPU debug label so staging and storage paths stay consistent.

Supersedes the approach of excluding StorageBuffer from device.buffers (e.g. PR #8690).

[Copilot]

Pull request overview

This pull request fixes WebGPU device lose/restore handling for StorageBuffer by ensuring storage buffers are tracked by GraphicsDevice.buffers and participate in the same context loss / restoration lifecycle as other tracked buffers, preventing crashes and stale GPUBuffer references after device re-creation.

Changes:

• Track StorageBuffer instances in GraphicsDevice.buffers, remove them on destroy(), and implement loseContext() / restoreContext() with documented “contents undefined” semantics.
• Update GraphicsDevice.restoreContext() to call buffer.restoreContext() instead of unlock(); add @ignore restoreContext() shims to VertexBuffer / IndexBuffer.
• Improve WebGPU buffer handling by nulling WebgpuBuffer.buffer on context loss and consistently applying GPU debug labels during allocation.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/platform/graphics/webgpu/webgpu-buffer.js	Clears stale GPUBuffer references on device loss and applies labels in allocate() so restore paths are labeled consistently.
src/platform/graphics/vertex-buffer.js	Adds internal restoreContext() delegating to unlock() to preserve existing public API while supporting new restore iteration.
src/platform/graphics/storage-buffer.js	Registers storage buffers for device tracking and adds lose/restore context methods; documents post-restore undefined contents behavior.
src/platform/graphics/index-buffer.js	Adds internal restoreContext() delegating to unlock() to work with GraphicsDevice.restoreContext() changes.
src/platform/graphics/graphics-device.js	Switches buffer restoration loop from unlock() to restoreContext() and clarifies behavior for storage buffers.

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