Introducing the v0 composite model family

What this post added

Introduces the composite model architecture for v0, combining RAG, LLMs, and a custom streaming post-processing model for improved code generation quality. Details the pre-processing steps, the use of state-of-the-art base models (including upgrades like Sonnet 3.7 to Sonnet 4), and the custom AutoFix model (`vercel-autofixer-01`) trained with RFT for faster and more reliable error correction. Presents performance benchmarks comparing v0 models against base models and other LLMs, highlighting `v0-1.5-lg`'s strength in specialized reasoning and larger context windows. Discusses future plans for model improvements and new model classes.