fix(client): inline embedded specs when parsing YAML

[synackd]

Description

Flat YAML payloads only populated the wrapper's name field for fabrica service resource specs (e.g. BootConfigSpec) because yaml.v3 does not automatically inline anonymous embedded structs. As a result, fields such as kernel, initrd, params, and macs were silently ignored and empty specs were sent to the service.

Add the yaml:",inline" tag to every simple API spec wrapper so YAML fields are decoded into their embedded boot-service and metadata-service specifications. Do not add an equivalent JSON tag because encoding/json already promotes fields from anonymous embedded structs.

Add regression tests covering flat YAML decoding for boot configurations, BMCs, nodes, cluster defaults, groups, instance information, and WireGuard peers. This ensures the CLI's YAML and JSON payload formats retain the same flat simple-API structure.

Checklist

• My code follows the style guidelines of this project
• I have added/updated comments where needed
• I have added tests that prove my fix is effective or my feature works
• I have run make test (or equivalent) locally and all tests pass
• I have updated the relevant documentation (CLI examples, man pages, README, other docs, etc.)
• DCO Sign-off: All commits are signed off (git commit -s) with my real name and email
• REUSE Compliance:
  • Each new/modified source file has SPDX copyright and license headers
  • Any non-commentable files include a <filename>.license sidecar
  • All referenced licenses are present in the LICENSES/ directory

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Dependency update

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[synackd]

Hotfix for issue found when testing OpenCHAMI/release#50 with OpenCHAMI/openchami.org#100. Tests and checks passing.