Add WallGuard Professional Workroom contract

[mdheller]

Superseded by #540, which replayed this WallGuard Professional Workroom product-contract slice onto current main and merged as 593fbdc86deda3c7617e8f26d494e734a4bf5bdd.

Content capture verified before closure:

• contracts/wallguard/professional-workroom.example.json
• tools/validate_wallguard_professional_workroom.py
• Makefile target wiring for validate-wallguard-professional-workroom

Boundary preserved:

• contract/fixture validation only
• no live UI implementation
• no middleware implementation
• no policy evaluation implementation
• no runtime enforcement implementation
• no service endpoints
• no database schema
• no deployment wiring

No content is being discarded; this stale/non-mergeable predecessor is closed only after the replacement PR landed.

[mdheller]

Parking this PR as open, not abandoned.

Current status after rerunning failed jobs on head 01d0f0df523e9c452e60f9f53dedfd8218fc7b4f:

• PR is mergeable.
• Passing workflows include: brokerage-validation, workspace-operation-runtime, SVF Validation, platform-wave1-stubs, platform-contracts-check, validate-change-v2-api-stub, FogStack Kubernetes Manifests, cloudshell-fog structural conformance v2/v3, FogStack Local Demo, and premerge-audit.
• Still failing workflows:
  • ci, job build-web
  • validate, job validate, step Validate
• The GitHub connector log output is truncated before the actionable failure lines, and string search over the returned resource does not expose the failing command or error.

Implemented scope in this PR:

• contracts/wallguard/professional-workroom.example.json
• tools/validate_wallguard_professional_workroom.py
• make validate-wallguard-professional-workroom

Recommended next step before merge: inspect full CI logs or run make validate-wallguard-professional-workroom plus the repo validate target locally. Do not merge while ci and validate remain red.