Update ai settings

Update workspace AI settings. Shared keys only. Agent model overrides stay separate from tool calling. JEV tasks are opt-in. Free endpoints do not receive private workspace context.

curl -X PUT "https://app.pipeline.help/api/workspaces/00000000-0000-4000-8000-000000000000/ai-settings" \
  -H "Authorization: Bearer $PIPELINE_API_KEY"

{
  "type": "object",
  "properties": {
    "success": {
      "type": "boolean"
    },
    "error": {
      "type": "string"
    }
  },
  "required": [
    "success"
  ]
}