llama.cpp b9716 Builds: InternVL Multimodal Batching, CUDA col2im, and Nginx SSE Fix

llama.cpp shipped over a dozen builds on June 18–19 (b9702–b9716). Key additions: batching support for InternVL multimodal models in the mtmd pipeline, a CUDA col2im 1D operation, a streaming fix adding `X-Accel-Buffering: no` header to prevent Nginx from buffering SSE responses, and HTTP 400 errors for invalid grammar inputs instead of silent drops. Server schema and request validation were also added.