feature: user-selectable capture hotkey with recorder in Settings

Sources/Shotdeck/SettingsView.swift

@@ -4,6 +4,8 @@ import ShotdeckCore
 
 struct SettingsView: View {
     @Environment(AppModel.self) private var model
+    @State private var isRecordingHotkey = false
+    @State private var recorder = HotkeyRecorderBox()
 
     private let labelWidth: CGFloat = 104
 
@@ -16,13 +18,19 @@ struct SettingsView: View {
                     .gridCellColumns(2)
             }
 
-            GridRow(alignment: .firstTextBaseline) {
+            GridRow(alignment: .center) {
                 fieldLabel("Capture")
-                Text("⌥⇧2 — fixed in this version")
-                    .foregroundStyle(.secondary)
-                    .lineLimit(1)
-                    .frame(maxWidth: .infinity, alignment: .leading)
-                    .frame(minHeight: 22, alignment: .leading)
+                HStack(spacing: 8) {
+                    Button {
+                        armHotkeyRecorder()
+                    } label: {
+                        Text(isRecordingHotkey ? "Press keys…" : model.hotkeyDisplayString)
+                            .foregroundStyle(isRecordingHotkey ? .secondary : .primary)
+                            .lineLimit(1)
+                    }
+                    Spacer(minLength: 0)
+                }
+                .frame(minHeight: 22)
             }
 
             GridRow {
@@ -57,6 +65,35 @@ struct SettingsView: View {
         .padding(16)
         .frame(minWidth: 320, idealWidth: 360, maxWidth: 360, alignment: .leading)
         .controlSize(.small)
+        .onDisappear { disarmHotkeyRecorder() }
+    }
+
+    private func armHotkeyRecorder() {
+        guard !isRecordingHotkey else { return }
+        isRecordingHotkey = true
+        recorder.onKey = { keyCode, flags in
+            handleRecorderKey(keyCode: keyCode, flags: flags)
+        }
+        recorder.arm()
+    }
+
+    private func handleRecorderKey(keyCode: UInt16, flags: NSEvent.ModifierFlags) {
+        if keyCode == 53 { // kVK_Escape
+            disarmHotkeyRecorder()
+            return
+        }
+        guard let pref = HotkeyPreference.fromKeyEvent(keyCode: keyCode, modifierFlags: flags) else {
+            return
+        }
+        pref.save()
+        model.reRegisterHotkey()
+        disarmHotkeyRecorder()
+    }
+
+    private func disarmHotkeyRecorder() {
+        recorder.disarm()
+        recorder.onKey = nil
+        isRecordingHotkey = false
     }
 
     private func fieldLabel(_ title: String) -> some View {
@@ -80,6 +117,35 @@ struct SettingsView: View {
     }
 }
 
+/// Local keyDown monitor for the Settings capture-hotkey recorder. Callbacks hop onto the
+/// main actor the same way `RegionPickerController` does — local monitors fire on the
+/// main run loop during `NSApp.sendEvent`.
+@MainActor
+private final class HotkeyRecorderBox {
+    var onKey: ((UInt16, NSEvent.ModifierFlags) -> Void)?
+    private var monitor: Any?
+
+    func arm() {
+        disarm()
+        monitor = NSEvent.addLocalMonitorForEvents(matching: .keyDown) { [weak self] event in
+            guard let self else { return event }
+            let keyCode = event.keyCode
+            let rawFlags = event.modifierFlags.rawValue
+            MainActor.assumeIsolated {
+                self.onKey?(keyCode, NSEvent.ModifierFlags(rawValue: rawFlags))
+            }
+            return nil
+        }
+    }
+
+    func disarm() {
+        if let monitor {
+            NSEvent.removeMonitor(monitor)
+        }
+        monitor = nil
+    }
+}
+
 extension AppModel: SettingsWindowPresenting {
     private static var settingsWindowController: NSWindowController?