feat: preserve native route assembly provenance

[shaggitza]

Summary

• preserve immutable side-qualified native root, object, registration, include, and mount provenance
• map target/baseline structural ownership with occurrence-sensitive endpoint identity
• publish schema-v4 JSON/YAML provenance with validated assembly invariants

Validation

• 42 route-provenance/formatter tests passed
• 539 secure-AST tests passed, 4 Python-version skips
• 36 registry/change-mapper/SCIP tests passed
• Ruff, strict mypy, diff checks, and independent terminal review passed

Part of #277; broader lifecycle reconciliation remains follow-up scope.