This paper focuses on the utilization of unmanned aerial vehicles (UAVs) with integrated artificial intelligence (AI) and ground robots (GERs) for emergency rescue operations in unknown environments. To overcome the computational limitations of a single UAV, we propose a cooperative framework that includes UAVs, GERs, and airships. The framework provides computational services for offloaded tasks by enabling resource pooling through UAV-GER (U2G) and UAV-Airship (U2A) links. We formulate the multi-objective problem of task assignment and navigation as a long-term dynamic optimization problem, aiming to minimize task completion time and energy consumption while ensuring stability. We transform the problem into a per-slot deterministic problem using Lyapunov optimization, and propose HG-MADDPG, which combines the Hungarian algorithm and GDM-based multi-agent deep deterministic policy gradient descent. Simulation results demonstrate significant improvements in offloading efficiency, latency, and system stability compared to baselines.