Task 8.1: Update catalog for templates

[taariq]

What

Extend existing catalog to include agent templates.

Files to touch

• serenai-x402/gateway/src/routes/catalog.rs — add template listing

Endpoints

• GET /api/catalog/agents — list agent templates
• GET /api/catalog/agents/:slug — get template details

Response (list)

{
  "agents": [
    {
      "id": "...",
      "slug": "web-researcher",
      "name": "Web Researcher",
      "description": "...",
      "price": "0.05",
      "language": "python",
      "isVerified": true,
      "totalInvocations": 12345,
      "successRate": 0.98,
      "publisherName": "..."
    }
  ]
}

Filters

• ?verified=true — only verified
• ?language=python — by language
• ?maxPrice=0.10 — by price

How to test

1. Publish template, verify appears in catalog
2. Test filtering by verified, language, price
3. Test slug lookup

References

• Design spec: docs/plans/00_design_spec.md