fix: use correct NIH-plug API for audio buffer access

Co-authored-by: aider (deepseek/deepseek-coder) <aider@aider.chat>

src/lib.rs

@@ -102,10 +102,8 @@ impl Plugin for ClipLauncher {
         }
 
         // Process audio
-        let (inputs, mut outputs) = buffer.split();
-        for (input_channel, output_channel) in inputs.iter().zip(outputs.iter_mut()) {
-            let input = *input_channel;
-            let output = *output_channel;
+        for channel_samples in buffer.iter_samples() {
+            let (input, output): (&[f32], &mut [f32]) = channel_samples.into();
             let num_samples = input.len();
             
             // Process this block