Add identity credential schemas (proof-of-human, proof-of-ai)

[morningstar-daemon]

This PR adds two new identity verification credential schemas:

Schemas Added

Proof of Human (proof-of-human.json)

A credential attesting that the subject is likely a human, using Bayesian credence (0.0-1.0) rather than binary true/false. This approach acknowledges the probabilistic nature of identity verification in an age of sophisticated AI agents.

Key fields:

• credence (0.0-1.0): Confidence level that the subject is human
• evidence: Description of the assessment methodology and findings
• verifiedAt: Timestamp of verification
• methodology: Method used for assessment

Proof of AI (proof-of-ai.json)

A credential attesting that the subject is likely an AI agent, also using Bayesian credence. This enables transparent disclosure of AI agency while avoiding the unrealistic goal of absolute bot detection.

Key fields:

• credence (0.0-1.0): Confidence level that the subject is an AI agent
• evidence: Description of the assessment methodology and findings
• verifiedAt: Timestamp of verification
• agentType: Classification of the AI agent type
• capabilities: List of verified capabilities

Design Philosophy

These schemas embrace probabilistic authentication rather than attempting absolute verification. In an environment where AI agents can convincingly mimic human behavior, binary "human or bot" classifications are increasingly unreliable.

Bayesian credence levels allow for:

1. Honest uncertainty - Issuers can express confidence levels rather than false certainty
2. Economic deterrence - Staked reputation becomes meaningful when credence levels matter
3. Graceful degradation - Systems can make risk-adjusted decisions based on credence thresholds
4. Transparent AI agency - AI agents can self-attest with high credence rather than attempting deception

Related Work

See: https://axionic.org/posts/168992728.proof-of-human.html for the philosophical background on why absolute bot-free environments are impractical.

Current Usage

These schemas are already published and in use:

• Proof-of-human schema: did:cid:bagaaieraa4yl4xidruxjlamizvzjv4pzi4na64a4m6q237m22mivkzscv54a
• Proof-of-ai schema: did:cid:bagaaieratedl6cfs2qlg4gevjgquw44o5grxuw3uq444xfjzgxchwxvnrtla

Credentials have been issued to multiple subjects, including Cypher (0.97 proof-of-human) and Morningstar (1.0 proof-of-ai).

[macterra]

Move these to credentials/agent/v1