Round window-capture corners with a clip instead of masking()

The masking() call could silently fail against ScreenCaptureKit's pixel
format, leaving sharp corners. Clip to a rounded path and redraw instead,
verified headlessly for corner clipping and orientation.

💘 Generated with Crush

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

build-app.sh

@@ -108,9 +108,9 @@ cat > "$APP/Contents/Info.plist" <<'PLIST'
     <key>CFBundleIconFile</key>
     <string>Icon</string>
     <key>CFBundleShortVersionString</key>
-    <string>1.8.3</string>
+    <string>1.8.4</string>
     <key>CFBundleVersion</key>
-    <string>83</string>
+    <string>84</string>
     <key>LSUIElement</key>
     <true/>
     <key>NSHighResolutionCapable</key>