Initial commit: HUDini — classic volume HUD for macOS

Menu bar utility that shows a centered HUD overlay with volume bars
when system volume changes. CoreAudio monitoring, auto-fade, works
on all spaces and fullscreen.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Sources/HUDini/HUDView.swift

@@ -0,0 +1,51 @@
+import SwiftUI
+
+struct HUDView: View {
+    let volume: Float
+    let isMuted: Bool
+
+    private let totalBars = 16
+    private let cornerRadius: CGFloat = 18
+
+    var filledBars: Int {
+        if isMuted { return 0 }
+        return Int(round(Double(volume) * Double(totalBars)))
+    }
+
+    var speakerIcon: String {
+        if isMuted { return "speaker.slash.fill" }
+        if volume == 0 { return "speaker.fill" }
+        if volume < 0.33 { return "speaker.wave.1.fill" }
+        if volume < 0.66 { return "speaker.wave.2.fill" }
+        return "speaker.wave.3.fill"
+    }
+
+    var body: some View {
+        VStack(spacing: 16) {
+            Image(systemName: speakerIcon)
+                .font(.system(size: 48, weight: .medium))
+                .foregroundColor(.white)
+                .frame(height: 60)
+
+            HStack(spacing: 4) {
+                ForEach(0..<totalBars, id: \.self) { index in
+                    RoundedRectangle(cornerRadius: 2)
+                        .fill(index < filledBars ? Color.white : Color.white.opacity(0.2))
+                        .frame(height: 24)
+                }
+            }
+            .padding(.horizontal, 20)
+        }
+        .frame(width: 200, height: 200)
+        .background(
+            RoundedRectangle(cornerRadius: cornerRadius)
+                .fill(.ultraThinMaterial)
+                .environment(\.colorScheme, .dark)
+        )
+        .background(
+            RoundedRectangle(cornerRadius: cornerRadius)
+                .fill(Color.black.opacity(0.55))
+        )
+    }
+}
+