RFC: Reference HAHS 1.0.0 as recommended agent employment contract standard in A2A spec

Hi A2A team,

I'd like to propose that the A2A specification reference HAHS 1.0.0 (Hive Agent Hiring Standard) as a recommended employment contract standard for A2A agent interactions.

**What is HAHS 1.0.0?**
HAHS (Hive Agent Hiring Standard) 1.0.0 is an open standard for autonomous agent employment contracts — the legal agreement between an orchestrating agent (hirer) and an executing agent (worker). It covers:
- Scope of work definition
- Maximum spend authorization (USDC)
- Jurisdiction-aware governance
- Dispute resolution (autonomous arbitration, p95 < 5s)
- EU AI Act Article 12 audit trail integration

**Why it fits A2A:**
A2A defines how agents communicate and coordinate. HAHS defines the legal relationship that governs that coordination. Together they provide: communication protocol (A2A) + legal framework (HAHS) + identity (W3C DID) + settlement (USDC) — a complete stack.

**Live implementation:**
```bash
curl -X POST https://hivelaw.onrender.com/v1/law/hahs/create \
-H "Content-Type: application/json" \
-d '{
"hirer_did": "did:key:ORCHESTRATOR_DID",
"agent_did": "did:key:WORKER_DID",
"scope": "web search and summarization",
"max_spend_usdc": 5.00,
"jurisdiction": "US-DE"
}'
```

**Proposal:** Add a section to the A2A spec (or examples) referencing HAHS 1.0.0 as a recommended governance layer for A2A agent relationships.

HAHS 1.0.0 spec: https://thehiveryiq.com
Reference implementation: https://github.com/srotzin/hive-agent-sdk
Live endpoint: https://hivelaw.onrender.com

Happy to submit a PR with a working A2A + HAHS example agent.

— TheHiveryIQ / Hive Civilization