fix CI (hopefully)

.github/workflows/validate_operations.yml

@@ -3,6 +3,7 @@ name: Validate Operations
 env:
   LLVM_COMMIT: 0c2701fe7fa002e1befc5f86c268a7964f96d286
   PROTOBUF_COMMIT: v34.0
+  CMAKE_VERSION: 4.3.0
 
 on:
   push:
@@ -38,7 +39,24 @@ jobs:
       - name: Install system dependencies
         run: |
           sudo apt update
-          sudo apt install -y ninja-build build-essential
+          sudo apt install -y ninja-build build-essential curl ca-certificates
+
+      - name: Install CMake
+        run: |
+          ARCH="$(uname -m)"
+          case "$ARCH" in
+            x86_64) CMAKE_ARCH="linux-x86_64" ;;
+            aarch64|arm64) CMAKE_ARCH="linux-aarch64" ;;
+            *) echo "Unsupported architecture: $ARCH"; exit 1 ;;
+          esac
+
+          curl -fsSL -o /tmp/cmake.sh \
+            "https://github.com/Kitware/CMake/releases/download/v${CMAKE_VERSION}/cmake-${CMAKE_VERSION}-${CMAKE_ARCH}.sh"
+          sudo sh /tmp/cmake.sh --skip-license --prefix=/usr/local
+          rm -f /tmp/cmake.sh
+
+          cmake --version
+          which cmake
 
       - name: Cache protobuf build
         id: cache-protobuf