Optimize visualizer: 16 bins mirrored, Material You colors

- Reduce FFT to 30fps with 16 bins (mirrored to 32 visual bars)
- Use 1024 FFT size for faster processing
- Extract dominant colors from album artwork
- Center artwork with track info and quality badge
- Bars render from edges inward with color gradient

src-tauri/src/visualizer/fft_processor.rs

@@ -175,7 +175,7 @@ mod tests {
     #[test]
     fn test_log_frequency_distribution() {
         // Verify that frequency bars are logarithmically distributed
-        let num_bars = 64;
+        let num_bars = NUM_BARS; // Use the actual constant
         let min_log = 20.0_f32.ln();
         let max_log = 20000.0_f32.ln();
 
@@ -189,8 +189,9 @@ mod tests {
         // First bar should be around 20Hz
         assert!(freqs[0] > 19.0 && freqs[0] < 25.0);
 
-        // Middle bar (~32) should be around 630Hz (geometric mean of 20 and 20000)
-        assert!(freqs[32] > 500.0 && freqs[32] < 800.0);
+        // Middle bar (~16 for 32 bars) should be around 630Hz (geometric mean of 20 and 20000)
+        let mid = num_bars / 2;
+        assert!(freqs[mid] > 500.0 && freqs[mid] < 800.0);
 
         // Last bar should approach 20000Hz
         assert!(freqs[num_bars - 1] > 15000.0);

src-tauri/src/visualizer/mod.rs

@@ -17,14 +17,15 @@ use std::sync::atomic::{AtomicBool, AtomicU32, Ordering};
 use tauri::AppHandle;
 
 /// Number of frequency bins to send to frontend
-pub const NUM_BARS: usize = 64;
+/// 16 bins, mirrored on frontend for symmetric look
+pub const NUM_BARS: usize = 16;
 
 /// FFT size (must be power of 2)
-/// 2048 gives good frequency resolution at ~21Hz per bin at 44.1kHz
-pub const FFT_SIZE: usize = 2048;
+/// 1024 is faster than 2048 and still gives ~43Hz resolution at 44.1kHz
+pub const FFT_SIZE: usize = 1024;
 
 /// Target frames per second for visualization updates
-pub const TARGET_FPS: u64 = 60;
+pub const TARGET_FPS: u64 = 30;
 
 /// Shared state for visualization that can be passed to the audio thread
 #[derive(Clone)]