style: apply rustfmt across all crates and demos

Consistent formatting pass: line wrapping, import sorting, trailing
whitespace removal, let-chain indentation, merged derive attributes,
and unsafe block reformatting.

Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>

crates/specialized/rtx-geom/src/layers/sparse_gcn.rs

@@ -121,9 +121,9 @@ impl SparseGCNLayer {
 
         tracing::info!(
             "Sparse GCN setup complete. cuSPARSE acceleration: {}",
-            self.message_passing
-                .as_ref()
-                .is_some_and(super::super::sparse_message::SparseMessagePassing::has_cusparse_acceleration)
+            self.message_passing.as_ref().is_some_and(
+                super::super::sparse_message::SparseMessagePassing::has_cusparse_acceleration
+            )
         );
 
         Ok(())