Add yaml decode function for machine info

[jpm-canonical]

Add YAML decoders for machine info and devices. This is required for backwards compatibility in the inference snap cli.

[Copilot]

Pull request overview

Adds YAML decoding support for MachineInfo and devices, while also renaming existing JSON decode entrypoints to make the format explicit.

Changes:

• Renamed Decode → DecodeJSON across machine and device decode APIs.
• Added YAML decode paths: machine.DecodeYAML, device.DecodeYAML, and per-bus DecodeYAML.
• Updated/extended tests to cover the new decode functions (including YAML machine info decoding).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
pkg/machine/machine_golden_test.go	Updates golden test to use DecodeJSON.
pkg/machine/device/usb/usb.go	Renames JSON decode function and adds YAML decode for USB devices.
pkg/machine/device/usb/usb_test.go	Updates tests to use DecodeJSON.
pkg/machine/device/pci/pci.go	Renames JSON decode function and adds YAML decode for PCI devices.
pkg/machine/device/pci/pci_test.go	Updates tests to use DecodeJSON.
pkg/machine/device/fastrpc/fastrpc.go	Renames JSON decode function and adds YAML decode for FastRPC devices.
pkg/machine/device/decode.go	Introduces DecodeJSON and new DecodeYAML dispatch by bus.
pkg/machine/device/decode_test.go	Updates tests to use DecodeJSON.
pkg/machine/decode.go	Introduces DecodeJSON and new DecodeYAML for machine info.
pkg/machine/decode_test.go	Updates JSON decode tests and adds YAML machine info decode tests.

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[farshidtz]

Thanks. The changes are fine, but I'm not sure why this is needed in order to keep the inference snaps CLI backward compatible. That feels like a requirement that must be satisfied on the CLI module, although that is currently in beta and undergoing major changes anyway.

[jpm-canonical]

Closing this as the team decided not to add YAML decoding support to lscompute at this stage. We are going to change modelctl debug select to only support JSON.