NVIDIA JetPack 7.2.1 adds agentic video skills and T3000 emulation

JetPack 7.2.1 brings PyNvVideoCodec 2.2 to Jetson Thor for the first time, NVIDIA's Python library for GPU-accelerated video encode/decode, exposing GPU-resident frames via DLPack and CUDA buffers. It also adds agentic video skills for device discovery, pipeline execution, and reproducible verification. JetPack 7.1 previously added the C/C++ Video Codec SDK on Thor.