Darwin Nix desktop app does not set the Dock icon

[colonelpanic8]

Environment

• Platform: macOS (Darwin arm64)
• Package: nix build .#desktop
• Paseo version inspected: 0.2.5

Reproduction

1. Build the desktop package on macOS:

   $ nix build .#desktop

2. Launch the resulting app through the Nix package launcher:

   $ ./result/bin/paseo-desktop

3. Observe the app icon in the Dock.

Actual result

The running desktop app does not consistently display the Paseo icon when launched from the Darwin Nix package.

Expected result

The running desktop app displays the Paseo icon in the Dock.

Raw investigation evidence

The generated bundle declares and includes the ICNS resource:

$ /usr/libexec/PlistBuddy -c 'Print :CFBundleIconFile' \
    result/Applications/Paseo.app/Contents/Info.plist
icon.icns

$ find result/Applications/Paseo.app/Contents/Resources \
    -maxdepth 1 -iname '*.icns' -print
result/Applications/Paseo.app/Contents/Resources/icon.icns

The ICNS in a built Nix output is byte-identical to the source asset:

$ shasum -a 256 packages/desktop/assets/icon.icns \
    result/Applications/Paseo.app/Contents/Resources/icon.icns
1f251e08249cd3e3712892fcce093c6ed86bae51f0ebbf9d5049fe8e40d74eda  packages/desktop/assets/icon.icns
1f251e08249cd3e3712892fcce093c6ed86bae51f0ebbf9d5049fe8e40d74eda  result/Applications/Paseo.app/Contents/Resources/icon.icns

The packaged resources do not contain the PNG requested by the runtime Dock-icon code:

$ ls result/Applications/Paseo.app/Contents/Resources/icon.png
ls: result/Applications/Paseo.app/Contents/Resources/icon.png: No such file or directory