Add TensorRT-LLM audio and V2V guide

[ishovkun]

Summary

• extend the existing TensorRT-LLM audiovisual notebook with Nano and Super text-to-video and image-to-video audio examples
• add Nano and Super video-to-video examples using the merged multipart input_reference API
• document the ffmpeg requirement for MP4 encoding and synchronized audio muxing
• update the shared setup, audiovisual quickstart, and root example index

TensorRT-LLM runtime support is available through NVIDIA/TensorRT-LLM#14827 (audio) and NVIDIA/TensorRT-LLM#16155 (V2V).

Validation

• validated notebook JSON, unique cell IDs, and empty execution outputs
• compiled all notebook code cells and README Python examples
• generated every Nano and Super payload and validated referenced assets
• validated audio JSON and image/video multipart curl construction with mocked server responses
• git diff --check

Full GPU inference was not run as part of this documentation-only change.

[ConstBob]

LGTM. Checked docs/notebook consistency for the new audio and V2V paths, verified referenced assets exist. Validated Nano/Super payload generation plus JSON/multipart request construction (enable_audio, input_reference, V2V conditioning fields). Notebook JSON/cell IDs and example snippets look clean. Approve.

[MaciejBalaNV]

LGTM