[RFC] Policy Facilitator pattern for Agentic Wallets — Dreamline as reference implementation

## Problem

Agentic Wallets give agents autonomous spending power.
The built-in guardrails (spending caps, OFAC screening) are static
and centralized in CDP infrastructure.

There is no standard way for developers to add:
- Custom destination whitelists/blacklists
- Per-agent policy rules (max per tx, daily budget)
- Immutable on-chain enforcement that survives server compromise

## Proposal

A **Policy Facilitator** pattern for x402-compatible Agentic Wallets.

Instead of routing payments directly to `https://api.cdp.coinbase.com/platform/v2/x402`,
agents route to a policy facilitator first:

Agent → POST /facilitator/verify (Dreamline)
→ on-chain blacklist check ✓
→ policy check ✓
→ approved → CDP settlement as normal

## Live implementation

- Facilitator: https://dreamline-backend.onrender.com/facilitator/supported
- On-chain registry: `0x71dA6F5b106E3Fb0B908C7e0720aa4452338B8BE` (BNB Chain)
- SDK: `npm install dreamline-x402`
- GitHub: https://github.com/aisatoshinext-arch/dreamline

## Integration (3 lines)

const { createDreamlineClient } = require('dreamline-x402');
const fetch = createDreamlineClient({ apiKey: 'dlk_your_key' });
await fetch('https://api.example.com/paid-resource');

## Request

1. Document the Policy Facilitator pattern as a standard extension point
2. Add facilitatorUrl as a configurable option in AgentKit
3. List Dreamline as a community facilitator in the x402 ecosystem

— @getdreamline