Add workstation contract family for doctor and fix reports

[mdheller]

We now have real workstation-v0 machine-readable outputs landing in SociOS-Linux/source-os:

• sourceos.doctor
• sourceos.fix.shell
• sourceos.fix.fish
• sourceos.fix.all

These are currently implementation-level JSON contracts inside the Linux realization repo.

We should promote them into the canonical typed-contract layer here.

Scope

• Add JSON Schemas for:
  • WorkstationDoctorReport
  • WorkstationFixShellReport
  • WorkstationFixFishReport
  • WorkstationFixAllReport
• Add conforming examples.
• Add schema-catalog entries in schemas/README.md.
• Optionally add a short docs note under docs/ describing the workstation contract tranche.

Why

• These reports are now part of the real operator/evidence surface for SourceOS workstation realization.
• source-os should implement them, but sourceos-spec should canonize them.
• Downstream consumers in agentplane, sociosphere, prophet-cli, and contractforge need a stable schema source.

Initial shape guidance

• Keep the current kind strings for compatibility (sourceos.doctor, sourceos.fix.shell, etc.).
• Require ok, summary, and typed result collections.
• Preserve additive evolution discipline (specVersion, semver-compatible expansion).

This issue is the contract-plane counterpart to the workstation-v0 program issue in SociOS-Linux/source-os.