Add Verifiable Audit Trail Plugin (VAL)

[aite550659-max]

Add Verifiable Audit Trail Plugin (VAL)

Problem:
Eliza agents need verifiable, tamper-proof records of their actions. Current logs are mutable and local-only - users must trust the agent operator.

Proposed Solution:
Add VAL (Verifiable Agent Log) plugin that automatically attests agent actions to immutable storage (Hedera HCS by default, works on any chain).

Example Usage:

import { VALPlugin } from '@elizaos/plugin-val';

const agent = new Agent({
  name: "MyAgent",
  plugins: [
    new VALPlugin({ topicId: "0.0.12345" })
  ]
});

// Every action is now attested to HCS - immutable & publicly verifiable

Benefits:

• Trust: Users can verify agent behavior independently
• Transparency: Public audit trail of all actions
• Security: Detect if agent behavior changes unexpectedly
• Compliance: Auditable records for regulated use cases

Why This Fits Eliza's Philosophy:
Eliza is about building agents "in the open" - VAL makes that transparency cryptographically verifiable. Every action is provable, not just claimed.

Specification:
https://github.com/aite550659-max/verifiable-agent-log

Reference Implementation:
https://github.com/aite550659-max/verifiable-agent-log/tree/main/integrations/eliza

Cost: $0.0008 per attestation ($30/year for 100 actions/day)

Would love to contribute this as an official Eliza plugin. Thoughts?