ci: consolidate rust + protoc install across workflows (#23700)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

scripts/ci/cuda/ci_install_gateway_dependencies.sh

@@ -1,24 +1,28 @@
 #!/bin/bash
+# Install dependencies for the sgl-model-gateway CI jobs.
+#
+# Gateway-specific apt deps are installed here; protoc and the Rust toolchain
+# are delegated to the shared installer (the toolchain version is pinned by
+# sgl-model-gateway/rust-toolchain.toml, picked up automatically on first
+# `cargo` invocation).
 set -euxo pipefail
 
-# Check if sudo is available
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+GATEWAY_APT_PACKAGES=(libssl-dev pkg-config redis-server)
 if command -v sudo >/dev/null 2>&1; then
     sudo apt-get update
-    sudo apt-get install -y libssl-dev pkg-config protobuf-compiler redis-server
+    sudo apt-get install -y "${GATEWAY_APT_PACKAGES[@]}"
 else
     apt-get update
-    apt-get install -y libssl-dev pkg-config protobuf-compiler redis-server
+    apt-get install -y "${GATEWAY_APT_PACKAGES[@]}"
 fi
 
-# Install rustup (Rust installer and version manager)
-curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y --default-toolchain 1.90
+bash "${SCRIPT_DIR}/../utils/install_rust_protoc.sh"
 
-
-# Follow the installation prompts, then reload your shell
+# Make cargo/rustc/protoc visible in this shell.
 . "$HOME/.cargo/env"
-source $HOME/.cargo/env
 
-# Verify installation
 rustc --version
 cargo --version
 protoc --version