refactor(ci): inline build steps, delete build-binary.sh

Replace build-binary.sh with discrete workflow steps: Build
mistralrs-server, Collect artifacts. Remove commented-out NCCL
check block.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

script/build-binary.sh

@@ -1,25 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-: "${FLAVOUR_NAME:?}"
-: "${CUDA_HOME:?}"
-: "${CARGO_FEATURES:?}"
-: "${CUDA_COMPUTE_CAP:?}"
-: "${SRC_DIR:?}"
-
-export PATH="${CUDA_HOME}/bin:${PATH}"
-export LD_LIBRARY_PATH="${CUDA_HOME}/targets/x86_64-linux/lib:${CUDA_HOME}/lib64:${LD_LIBRARY_PATH:-}"
-
-cd "${SRC_DIR}"
-
-# --locked ensures Cargo.lock is respected; fails loud if it's out of sync
-# rather than silently resolving to different versions.
-cargo build --release --locked --features "${CARGO_FEATURES}"
-
-mkdir -p ../artifacts
-cp target/release/mistralrs-server "../artifacts/mistralrs-server-${FLAVOUR_NAME}"
-
-# Also grab the other binaries if you want them
-cp target/release/mistralrs "../artifacts/mistralrs-${FLAVOUR_NAME}" 2>/dev/null || true
-
-echo "Built $(../artifacts/mistralrs-server-${FLAVOUR_NAME} --version 2>&1 | head -1)"