Enhance audio capture functionality and update dependencies

- Added support for capturing system audio on Windows using WASAPI with improved error handling and thread safety.
- Introduced the 'scopeguard' crate for better resource management during audio capture.
- Updated Cargo.toml to include 'scopeguard' and modified Windows-specific dependencies for enhanced functionality.
- Added a new test for validating audio capture output, ensuring the captured audio data is valid and non-empty.

tauri/src-tauri/tests/audio_capture_test.rs

@@ -0,0 +1,59 @@
+// NOTE: This test requires system audio to be playing during execution.
+// To run this test successfully:
+//   1. Start playing audio (music, video, etc.)
+//   2. Run: cargo test --test audio_capture_test -- --nocapture
+//   3. The test will capture audio for 5 seconds and verify the output
+
+use voicebox::audio_capture::{AudioCaptureState, start_capture, stop_capture};
+use base64::Engine;
+
+#[tokio::test]
+async fn test_system_audio_capture() {
+    // Create AudioCaptureState
+    let state = AudioCaptureState::new();
+
+    println!("Starting system audio capture with 5 second max duration...");
+
+    // Start capture with 5 second max duration
+    let result = start_capture(&state, 5).await;
+
+    if let Err(e) = result {
+        panic!("Failed to start capture: {}", e);
+    }
+
+    println!("Capture started, waiting 5 seconds...");
+
+    // Wait 5 seconds for capture to complete
+    tokio::time::sleep(tokio::time::Duration::from_secs(5)).await;
+
+    println!("Stopping capture...");
+
+    // Stop capture and get the result
+    let audio_data = stop_capture(&state).await;
+
+    match audio_data {
+        Ok(base64_wav) => {
+            println!("Capture stopped successfully");
+
+            // Validate the returned base64 WAV data
+            println!("Validating base64 WAV data...");
+
+            // Decode base64 to bytes
+            let decoded_bytes = base64::engine::general_purpose::STANDARD
+                .decode(&base64_wav)
+                .expect("Failed to decode base64 data");
+
+            // Verify bytes array is not empty
+            assert!(!decoded_bytes.is_empty(), "Decoded bytes array is empty");
+
+            // Confirm data has content (length > 0)
+            println!("WAV data length: {} bytes", decoded_bytes.len());
+            assert!(decoded_bytes.len() > 0, "WAV data has no content");
+
+            println!("✓ Test passed: Audio capture produced valid WAV data");
+        }
+        Err(e) => {
+            panic!("Failed to stop capture or get audio data: {}", e);
+        }
+    }
+}