Regenerate DMG from patched .app in fix-macos-local-build

The fix script rewrites the binary's libiconv reference from a Nix
store path to /usr/lib/libiconv.2.dylib and re-signs the .app, but the
DMG that `tauri build` already produced still embedded the un-patched
.app, so mounting and running from the DMG crashed at launch with a
code-signature mismatch on libiconv. After patching the .app, rebuild
the DMG from it with hdiutil so locally-produced DMGs run on the same
machine and on machines that do not have the Nix store.

Author: zonuexe

scripts/fix-macos-local-build.sh

@@ -21,3 +21,23 @@ codesign --force --deep --sign - "$APP_PATH"
 xattr -cr "$APP_PATH"
 
 echo "Patched and re-signed $APP_PATH"
+
+# The DMG that `tauri build` produced still embeds the un-patched .app.
+# Regenerate it from the patched .app so mounting and running from the
+# DMG no longer crashes with a libiconv code-signature mismatch.
+DMG_DIR="$(dirname "$(dirname "$APP_PATH")")/dmg"
+if [[ -d "$DMG_DIR" ]]; then
+  EXISTING_DMG="$(find "$DMG_DIR" -maxdepth 1 -name '*.dmg' -print -quit || true)"
+  if [[ -n "${EXISTING_DMG:-}" ]]; then
+    DMG_NAME="$(basename "$EXISTING_DMG")"
+    APP_NAME="$(basename "$APP_PATH" .app)"
+    rm -f "$EXISTING_DMG"
+    hdiutil create \
+      -volname "$APP_NAME" \
+      -srcfolder "$APP_PATH" \
+      -ov \
+      -format UDZO \
+      "$DMG_DIR/$DMG_NAME" >/dev/null
+    echo "Rebuilt $DMG_DIR/$DMG_NAME from patched .app"
+  fi
+fi