freetube: fix Darwin code signing

FreeTube 0.25.1 enables Electron-builder's ad-hoc signing by setting
mac.identity to "-". Electron-builder passes Apple codesign flags that
nixpkgs' sigtool does not support, causing the Darwin build to fail.

Disable Electron-builder signing and let autoSignDarwinBinariesHook add the
required ad-hoc signatures after installation.

Assisted-by: Codex (GPT-5)

pkgs/by-name/fr/freetube/package.nix

@@ -13,6 +13,7 @@
   makeShellWrapper,
   copyDesktopItems,
   electron,
+  darwin,
 
   nixosTests,
 }:
@@ -67,6 +68,9 @@ stdenvNoCC.mkDerivation (finalAttrs: {
     pnpm
     makeShellWrapper
     copyDesktopItems
+  ]
+  ++ lib.optionals stdenvNoCC.hostPlatform.isDarwin [
+    darwin.autoSignDarwinBinariesHook
   ];
 
   installPhase = ''

pkgs/by-name/fr/freetube/patch-build-script.patch

@@ -11,3 +11,12 @@ index bef1f6f1d..d2ee86611 100644
    appId: `io.freetubeapp.${packageDetails.name}`,
    copyright: 'Copyleft © 2020-2026 freetubeapp@protonmail.com',
    // asar: false,
+@@ -99,7 +101,7 @@ export default {
+     // Enable ad-hoc signing
+     // If we skip signing entirely, macOS says that the application is damaged, which makes users open bug reports.
+     // With an ad-hoc signature it still refuses to launch by default but with the reason that it cannot verify the signature
+-    identity: '-'
++    identity: null
+   },
+   win: {
+     icon: '_icons/icon.ico',