feat(auth): add AgentPass trust verification provider

[razashariff]

Adds AgentPassProvider -- agent identity and trust verification via AgentPass. Same pattern as the existing providers.

What it does

• Trust level check (L0-L4) with configurable minimum
• Trust score threshold (0-100)
• AML sanctions screening status
• Identity verification status
• Response caching (5 min default)
• Graceful degradation (onMissing: allow/reject)

Usage

import { MCPServer, AgentPassProvider } from "mcp-framework";

const server = new MCPServer({
  auth: {
    provider: new AgentPassProvider({
      minTrustScore: 50,
      minTrustLevel: "L2",
      requireCleanSanctions: true,
    }),
  },
});

Details

• Follows existing AuthProvider interface
• Zero new dependencies (native fetch)
• Public trust API -- no API key needed to query
• Live at agentpass.co.uk/api/trust/:agentName

Resolves #175