Endpoint: POST /api/openclaw/integrations/connected-account
Auth: X-Org-Token header (org service token)
CORS: Enabled (OPTIONS preflight supported)

Purpose: Check if a specific integration is connected for the organization and retrieve the connected account details.

Request Headers:
  X-Org-Token: <org-service-token>
  Content-Type: application/json

Request Body:
  integration (required, string): The integration slug to look up (e.g. "gmail", "slack")

Behavior:
  - Validates org token against database
  - Uses org.id as Composio user_id (connections are org-scoped)
  - Lists all ACTIVE connected accounts for the org
  - Finds the account matching the requested integration toolkit slug

Response 200:
  {
    "accountId": "conn_abc123",
    "userId": "org_xyz",
    "integration": "gmail",
    "status": "ACTIVE"
  }

Response 404 (not connected):
  {
    "error": "No active connected account found for integration gmail",
    "availableIntegrations": ["slack", "github"]
  }

Error Responses:
  401 - Missing or invalid X-Org-Token
  400 - integration is required
  404 - No active connected account found
  500 - Server error
