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]>

demos/rtx-neural-operator-demo/src/training.rs

@@ -402,7 +402,7 @@ pub struct LRScheduler {
 
 impl LRScheduler {
     /// Create a new LR scheduler.
-    #[must_use] 
+    #[must_use]
     pub fn new(scheduler_type: LRSchedulerType, initial_lr: f32) -> Self {
         Self {
             scheduler_type,
@@ -1292,7 +1292,7 @@ impl TrainingSession {
     }
 
     /// Start training in background
-    #[must_use] 
+    #[must_use]
     pub fn start(&self) -> tokio::task::JoinHandle<TrainingResult<String>> {
         let trainer = Arc::clone(&self.trainer);
         tokio::task::spawn_blocking(move || trainer.train())