fix(weather_scalar_file): use direct <= instead of !(>) for partial-ord guard

Clippy's `neg_cmp_op_on_partial_ord` lint fails on `-D warnings`,
which CI enforces. Using `<=` directly is clearer and equivalent for
the f64 inputs we pass (both are caller-supplied target pressures
that come from the level-key constants — neither is ever NaN).

rust/prop_grid_rs/src/weather_scalar_file.rs

@@ -309,7 +309,7 @@ fn compute_lapse_rate(sorted: &[&Level]) -> Option<f64> {
 }
 
 fn compute_layer_lapse_rate(sorted: &[&Level], lower_pres: f64, upper_pres: f64) -> Option<f64> {
-    if !(lower_pres > upper_pres) {
+    if lower_pres <= upper_pres {
         return None;
     }
     let lower = sorted