GET /api/keys

{
  "keys": [
    {
      "id": "key_123",
      "name": "Production Key",
      "keyPreview": "sk_abc1234...",
      "createdAt": "2026-03-01T00:00:00Z",
      "lastUsed": "2026-03-19T00:00:00Z"
    }
  ]
}

POST /api/keys

{
  "id": "key_456",
  "name": "Production Key",
  "key": "sk_a1b2c3d4e5f6...",
  "createdAt": "2026-03-19T00:00:00Z"
}

GET /api/keys/:id

{
  "id": "key_123",
  "name": "Production Key",
  "keyPreview": "sk_abc1234...",
  "createdAt": "2026-03-01T00:00:00Z",
  "lastUsed": "2026-03-19T00:00:00Z"
}

DELETE /api/keys/:id

{
  "success": true
}