Deepen architecture model (interfaces, attack surface, env variants, hierarchy, trust zones) and structure assumptions

[JohnASRG]

Motivation

The schema accepts architecture as a string or as a structured object with components and data flows, but the comprehensive example still uses a plain string — so the structured form is effectively undemonstrated. For real item-definition exchange across ISO 21434 and UN R155 stakeholders, the model also needs interfaces, attack-surface classification, environment variants, product hierarchy, trust zones, and safety relevance. Separately, assumptions are still free-text strings, which is too weak to support risk ownership and responsibility transfer between supplier and OEM.

Proposed change

1. architecture.interfaces[]: id, physical/logical type, protocol, direction (inbound|outbound|bidirectional), exposure (remote|adjacent|local|physical), trust zone reference.
2. architecture.trustZones[] and component.trustZoneId so zones become first-class with optional boundaryDescription and graphCoordinates (see related visualization issue).
3. component.attackSurface enum: remote | adjacent | local | physical | supplyChain | service | manufacturing.
4. itemDefinition.environment structured: markets[], vehiclePlatforms[], productionPhase, operationalPhase, serviceModes[].
5. Product hierarchy: component.kind enum (vehicle | system | ecu | softwareComponent | dataObject) and explicit parentComponentId semantics so a tree can be rendered.
6. Safety relevance: optional component.safetyRelevance with safetyGoalRef and asilContext (informational only — RDX does not assert ASIL ratings, only links them).
7. Structured assumption objects: { id, statement, owner, validityPeriod, responsibleParty, evidenceRefs[], riskSharingNote }. Keep a string-array form accepted for backwards compatibility, but mark deprecated.
8. Rewrite the comprehensive example to exercise structured architecture and structured assumptions end-to-end.

References

• spec/json/rdx.schema.json — architecture oneOf string|object
• examples/rdx-xml-comprehensive.xml — still uses string architecture
• AI peer review, section 4 ("Architecture support exists, but is still too lightweight") and section 2 (structured assumptions)

Acceptance criteria

• JSON Schema + XSD updated with all fields above (additive, backwards compatible)
• Comprehensive example exercises structured architecture, interfaces, trust zones, attack-surface classifications, and structured assumptions
• String forms of architecture and assumptions emit deprecation warnings in tools/validate.sh
• methodology/Methodology.md documents the new fields with one diagram

---

Surfaced by external AI peer review; see chat transcript for full review text.