Establish the Mojo 1.0 integration gate

tools/mojo-spike/abi.mojo

@@ -0,0 +1,3 @@
+@export("ds4_mojo_probe")
+def ds4_mojo_probe(value: Int32) abi("C") -> Int32:
+    return value

tools/mojo-spike/check.sh

@@ -0,0 +1,41 @@
+#!/bin/sh
+set -eu
+
+cd "$(dirname "$0")/../.."
+
+output_dir=target/mojo-spike
+mkdir -p "$output_dir"
+
+uv sync --frozen
+
+version=$(uv run --frozen --no-sync mojo --version)
+test "$version" = "Mojo 1.0.0 (ed45d567)"
+
+uv run --frozen --no-sync mojo build --emit object \
+    -o "$output_dir/abi.o" tools/mojo-spike/abi.mojo
+uv run --frozen --no-sync mojo build --emit shared-lib \
+    -o "$output_dir/libds4_mojo_probe.dylib" tools/mojo-spike/abi.mojo
+
+otool -L "$output_dir/libds4_mojo_probe.dylib" \
+    > "$output_dir/abi-closure.txt"
+nm -u "$output_dir/libds4_mojo_probe.dylib" \
+    > "$output_dir/abi-undefined.txt"
+
+grep -F '@rpath/libKGENCompilerRTShared.dylib' \
+    "$output_dir/abi-closure.txt" >/dev/null
+
+if uv run --frozen --no-sync mojo build \
+    -o "$output_dir/gpu-host" tools/mojo-spike/gpu_host.mojo \
+    > "$output_dir/gpu-host-build.txt" 2>&1; then
+    echo "unexpectedly found a GPU host runtime in the compiler-only environment" >&2
+    exit 1
+fi
+
+grep -F "unable to locate module 'max'" \
+    "$output_dir/gpu-host-build.txt" >/dev/null
+
+printf '%s\n' \
+    "Mojo 1.0 compiler and C ABI: verified" \
+    "Open Metal GPU host path: unavailable" \
+    "Shared-library runtime closure: @rpath/libKGENCompilerRTShared.dylib" \
+    "Decision: STOP until the runtime closure is explicitly redistributable"

tools/mojo-spike/gpu_host.mojo

@@ -0,0 +1,6 @@
+from max.gpu.host import DeviceContext
+
+
+def main() raises:
+    var context = DeviceContext()
+    print(context.name())