[Voltagent] Implement intelligent workflow orchestration for agents

### Is your feature request related to a problem? Please describe. While VoltAgent excels at creating highly capable individual agents, current approaches for larger problems often involve: Manual Chaining: Developers have to explicitly code the sequence of agent calls, data passing, and error handling for every multi-step process. This is time-consuming, prone to errors, and scales poorly for complex workflows. Lack of Adaptability: Predefined sequences struggle when faced with dynamic inputs, unexpected intermediate results, or when the optimal path isn't known beforehand. They lack the intelligence to adapt their execution based on real-time feedback. Absence of Goal-Oriented Autonomy: Developers need to manage the overall "project" or "goal" themselves, constantly checking if intermediate steps are truly leading to the final desired outcome. There's no inherent mechanism for the agents themselves to understand a higher-level objective and drive towards it autonomously through ite