proxyintegration: Re-implement user-mode NUMA node map

[will-j-wright]

We decided adding more kernel mode code wasn't the way to go, so this change delegates fetching the NUMA configuration to user-mode VMBus. Instead of calling a proxy IOCTL on the task start, we now accept a NUMA node map from user-mode VMBus in the proxy builder, which is passed down into the ProxyTask.

[github-actions]

⚠️ Unsafe Code Detected

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[Copilot]

Pull request overview

This PR refactors how NUMA node configuration is obtained by moving from a kernel-mode IOCTL approach to accepting the configuration from user-mode VMBus. Instead of the proxy integration calling into the kernel driver to fetch NUMA mappings at runtime, the configuration is now provided upfront through the builder pattern and passed into the ProxyTask.

Key Changes

• The ProxyIntegrationBuilder now accepts an optional VP-to-physical-node map via a new vp_to_physical_node_map() method
• The VpToPhysicalNodeMap struct changed from wrapping Vec<u8> to Option<Vec<u16>>, with values now being u16 instead of u8
• Removed the kernel-mode IOCTL (IOCTL_VMBUS_PROXY_GET_NUMA_MAP) and associated get_numa_node_map() method from the VmbusProxy implementation

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
vm/devices/vmbus/vmbus_server/src/proxyintegration.rs	Added builder method for NUMA map; changed VpToPhysicalNodeMap to use Option<Vec>; removed IOCTL-based map fetching from proxy_thread; updated field naming from numa_node_map to vp_to_physical_node_map for consistency
vm/devices/vmbus/vmbus_proxy/src/proxyioctl.rs	Removed IOCTL constant IOCTL_VMBUS_PROXY_GET_NUMA_MAP and associated struct VMBUS_PROXY_GET_NUMA_MAP_OUTPUT
vm/devices/vmbus/vmbus_proxy/src/lib.rs	Removed get_numa_node_map() method and associated imports (headervec, ERROR_MORE_DATA)
vm/devices/vmbus/vmbus_proxy/Cargo.toml	Removed headervec dependency which is no longer needed
Cargo.lock	Reflects removal of headervec dependency from vmbus_proxy

[github-actions]

At least one Petri test failed.

[github-actions]

At least one Petri test failed.

[SvenGroot]

See comment

[SvenGroot]

I would propagate this change back, there's no need to use an Option in the builder or anywhere.