feat(examples): add AgentLair agent platform integration example

[piiiico]

Summary

Adds a self-contained example demonstrating how AgentLair operates as the agent identity platform within a Verifiable Intent Autonomous mode delegation chain.

The VI spec explicitly lists "agent platform APIs" as out of scope. AgentLair fills this gap by providing agent keypair management (P-256), vault-based L3 signing, and hash-chained audit trails — the infrastructure layer that complements VI's authorization proof layer.

What the example covers

• Agent key provisioning: AgentLair provides the P-256 keypair bound as cnf.jwk in the L2 mandate
• L2 mandate creation: User delegates to AgentLair agent with constraints (amount limit, merchant allowlist, product allowlist)
• Vault-based L3 signing: AgentLair vault signs L3a (payment) and L3b (checkout) credentials — private key never leaves the vault
• Selective disclosure routing: Merchant and network each receive only the disclosures relevant to their role
• Chain + constraint verification: Both merchant and network verify the full delegation chain
• Audit trail: AgentLair records a hash-chained audit entry linked to the VI transaction ID

The example is self-contained, follows the same patterns as existing examples in examples/, and runs against the SDK with no additional dependencies.

How to run

pip install -e ".[dev]"
python examples/agentlair_integration.py

Test plan

• pytest passes (308 tests, 0 failures)
• python examples/agentlair_integration.py runs end-to-end successfully
• No changes to existing code — example-only addition
• DCO sign-off included

Signed-off-by: Håkon Åmdal hakon@amdal.dev