mic recorder: Show smoothed waveform on finish

src/components/MicRecorder.svelte

···
     bars = Array.from({ length: effectiveBarCount }, () => 0.08);
   }
 
+  function smoothBarsForStop(values: number[], passes = 2): number[] {
+    if (values.length < 3 || passes <= 0) return values;
+
+    let smoothed = [...values];
+    for (let pass = 0; pass < passes; pass += 1) {
+      const next = [...smoothed];
+      for (let i = 1; i < smoothed.length - 1; i += 1) {
+        const prev = smoothed[i - 1];
+        const current = smoothed[i];
+        const upcoming = smoothed[i + 1];
+        // Weighted moving average to mimic the visual easing while bars are in motion.
+        next[i] = Math.max(0.08, prev * 0.25 + current * 0.5 + upcoming * 0.25);
+      }
+      smoothed = next;
+    }
+
+    return smoothed;
+  }
+
   function getRecorderOptions(): MediaRecorderOptions | undefined {
     if (typeof MediaRecorder === "undefined" || !MediaRecorder.isTypeSupported) return undefined;
 
···
   function stopRecording() {
     if (!isRecording) return;
     isRecording = false;
-    bars = bars.map(() => 0.08);
+    bars = smoothBarsForStop(bars);
 
     if (frameId) {
       window.cancelAnimationFrame(frameId);