Fix flipped drawing when copying/saving annotated images

The strokes were stored in top-left image coordinates but drawn into an
AppKit CGContext with a bottom-left origin, so exports came out mirrored
and offset. Flip Y in the context before stroking so annotations land
where they were drawn.

💘 Generated with Crush

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

Sources/Kapture/ResultWindow.swift

@@ -149,6 +149,12 @@ final class CaptureModel: ObservableObject {
         let ctx = NSGraphicsContext.current!.cgContext
         // CGImage draws with a flipped Y in NSGraphicsContext
         ctx.draw(image, in: NSRect(origin: .zero, size: size))
+        // Strokes are stored in TOP-LEFT image coordinates (from the SwiftUI
+        // canvas), but the CGContext uses a BOTTOM-LEFT origin. Flip Y so the
+        // strokes land where they were drawn.
+        ctx.saveGState()
+        ctx.translateBy(x: 0, y: size.height)
+        ctx.scaleBy(x: 1, y: -1)
         ctx.setLineCap(.round)
         ctx.setLineJoin(.round)
         for stroke in strokes {
@@ -162,6 +168,7 @@ final class CaptureModel: ObservableObject {
             }
             ctx.strokePath()
         }
+        ctx.restoreGState()
         NSGraphicsContext.restoreGraphicsState()
         return rep.cgImage ?? image
     }