Integrate RAVEL development workloads with MNCS Fabric

[epi13]

Summary

• add development-only RAVEL Fabric workload and observation contracts
• execute branching/ring parity through the public Fabric LocalController/LocalWorker boundary
• retain Fabric records, receipts, bundles, challenges, replay and reconciliation identities
• add Forge-governed Fabric workflows, family compatibility lock, experience/memory references, package data, CI and documentation

Validation

• repository unit suite: 69 passed
• Fabric-specific suite: 6 passed
• direct local Fabric reference: branching and ring PASS
• Forge Fabric capability/reference/negative workflows: PASS
• GCC/Clang and ASAN/UBSAN: PASS
• wheel install and pip check: PASS
• family compatibility lock: fail-closed when the live Fabric checkout is dirty or drifts
• candidate remains unfrozen; no selection/final material consumed