feat(examples): add query_props example to print runtime device props (sm_52)

Provides a simple way to assert Tesla M40 (sm_52) selection at runtime via CudaContext::current_device_props().

Refs: #16

Co-authored-by: openhands <openhands@all-hands.dev>

Author: openhands-agent

examples/query_props.rs

@@ -0,0 +1,8 @@
+fn main() {
+    let ctx = m40_llm::cuda::CudaContext::new(-1).unwrap();
+    let p = ctx.current_device_props().unwrap();
+    println!(
+        "name={} major={} minor={} device_id={}",
+        p.name, p.major, p.minor, p.device_id
+    );
+}