[chain/appchain] Define appchain hardware node requirements

[FlowmemoryAI]

Objective

Define research-only requirements for FlowRouter or other hardware nodes that observe a future FlowMemory appchain, without making hardware nodes validators or data availability providers.

Allowed folders

• research/appchain/
• research/l1/ only for comparison notes
• docs/ARCHITECTURE.md only for cross-linking
• docs/SECURITY_MODEL.md only for threat-model updates

Forbidden folders

• Hardware CAD
• Firmware implementation
• Production decentralized internet design
• Validator economics or hardware-validator rewards
• Production appchain/L1 implementation
• Dashboard UI

Acceptance criteria

• Define hardware node roles as observer/cache/diagnostic roles, not required validators.
• Define what compact state can be relayed over low-bandwidth channels and what must not be relayed.
• Define freshness, stale-cache, replay, and tamper assumptions.
• Define minimum monitoring and operator diagnostics needed for appchain observation.
• Cross-link to appchain go/no-go criteria and existing hardware boundaries.

Risk level

Medium

Recommended agent

FlowMemory Chain / Appchain Agent with Hardware Agent review