feat: add floating transcription panel with auto-scroll and copy

MyVoxtral/MyVoxtral/Views/TranscriptionWindow.swift

@@ -0,0 +1,78 @@
+import SwiftUI
+import AppKit
+
+struct TranscriptionContentView: View {
+    @ObservedObject var manager: TranscriptionManager
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            HStack {
+                Circle()
+                    .fill(manager.isRecording ? .red : .gray)
+                    .frame(width: 8, height: 8)
+                Text(manager.isRecording ? "Recording..." : "Idle")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                Spacer()
+                Button {
+                    NSPasteboard.general.clearContents()
+                    NSPasteboard.general.setString(manager.currentText, forType: .string)
+                } label: {
+                    Image(systemName: "doc.on.doc")
+                }
+                .buttonStyle(.borderless)
+                .disabled(manager.currentText.isEmpty)
+            }
+
+            ScrollViewReader { proxy in
+                ScrollView {
+                    Text(manager.currentText.isEmpty ? "Transcription will appear here..." : manager.currentText)
+                        .frame(maxWidth: .infinity, alignment: .leading)
+                        .foregroundStyle(manager.currentText.isEmpty ? .secondary : .primary)
+                        .textSelection(.enabled)
+                        .id("bottom")
+                }
+                .onChange(of: manager.currentText) {
+                    proxy.scrollTo("bottom", anchor: .bottom)
+                }
+            }
+        }
+        .padding()
+        .frame(width: 320, height: 200)
+    }
+}
+
+final class TranscriptionPanel {
+    private var panel: NSPanel?
+    private let manager: TranscriptionManager
+
+    init(manager: TranscriptionManager) {
+        self.manager = manager
+    }
+
+    func show() {
+        if panel == nil {
+            let panel = NSPanel(
+                contentRect: NSRect(x: 0, y: 0, width: 320, height: 200),
+                styleMask: [.titled, .closable, .resizable, .nonactivatingPanel, .utilityWindow],
+                backing: .buffered,
+                defer: false
+            )
+            panel.title = "MyVoxtral"
+            panel.isFloatingPanel = true
+            panel.level = .floating
+            panel.contentView = NSHostingView(rootView: TranscriptionContentView(manager: manager))
+            panel.center()
+            self.panel = panel
+        }
+        panel?.orderFront(nil)
+    }
+
+    func hide() {
+        panel?.orderOut(nil)
+    }
+
+    var isVisible: Bool {
+        panel?.isVisible ?? false
+    }
+}