feat: support order property of coder_agent (#12121)

coderd/database/models.go

@@ -2243,6 +2243,8 @@ type WorkspaceAgent struct {
 	Subsystems  []WorkspaceAgentSubsystem `db:"subsystems" json:"subsystems"`
 	DisplayApps []DisplayApp              `db:"display_apps" json:"display_apps"`
 	APIVersion  string                    `db:"api_version" json:"api_version"`
+	// Specifies the order in which to display agents in user interfaces.
+	DisplayOrder int32 `db:"display_order" json:"display_order"`
 }
 
 type WorkspaceAgentLog struct {