Keep the captured app focused during selection

The overlay used to activate Kapture, pushing the target app into
background mode so its chrome (title bar, toolbar, tabs) was captured
dimmed. Input no longer needs activation — the event tap handles it — so
the overlay is a non-activating panel shown without taking focus, and the
app keeps its active appearance in the capture.

💘 Generated with Crush

Assisted-by: Crush:deepseek-v4-flash-0731

Sources/Kapture/OverlayView.swift

@@ -6,8 +6,11 @@ final class OverlayWindow: NSPanel {
     init(screen: NSScreen, controller: CaptureController) {
         let content = OverlayView()
         super.init(
+            // Non-activating: the overlay must NOT steal focus, so the app
+            // being captured keeps its active appearance (undimmed chrome).
+            // Input comes from the CGEventTap, not panel events.
             contentRect: screen.frame,
-            styleMask: [.borderless],
+            styleMask: [.borderless, .nonactivatingPanel],
             backing: .buffered,
             defer: false
         )