Method wouldCreateCycle

* Detect if adding a dependency would create a cycle. * Uses DFS to check if there's a path from depId back to taskId. * * @param taskId - The task that would have the new dependency * @param depId - The dependency being added * @param visited - Set of already visited nodes (for DFS)

(taskId: string, depId: string, visited: Set<string> = new Set())