macOS: fix arm64 bundle rejection (-10825) on macOS Sequoia

The Info.plist template shipped LSMinimumSystemVersion=12.3.0, but
the CMake build embedded the host SDK's deployment target (minos
26.0 on recent build machines) into the binary's LC_BUILD_VERSION.
Launch Services relies on the binary's minos, not the plist, so it
refused to launch the app on macOS < 26 even though it ran fine
when invoked directly.

- Set CMAKE_OSX_DEPLOYMENT_TARGET=14.0 explicitly in the cmake
  configure step, matching the real minimum imposed by the
  Homebrew Qt6 toolchain used for this build.
- Sync misc/Info.plist's LSMinimumSystemVersion to 14.0.0, and have
  MacQetDeploy_arm64_cmake.sh set it via PlistBuddy at bundle
  install time so it can't drift from the build target again.

Reported-by: guillaume.ruivo (forum)

misc/Info.plist

@@ -62,6 +62,6 @@
 	<key>NSPrincipalClass</key>
 	<string>NSApplication</string>
 	<key>LSMinimumSystemVersion</key>
-	<string>12.3.0</string>
+	<string>14.0.0</string>
 </dict>
 </plist>

misc/MacQetDeploy_arm64_cmake.sh

@@ -99,6 +99,7 @@ fi
 
 cmake -S . -B "$BUILD_DIR" -G Ninja \
     -DCMAKE_BUILD_TYPE=Release \
+    -DCMAKE_OSX_DEPLOYMENT_TARGET=14.0 \
     -DQT_VERSION_MAJOR=$QT_MAJOR \
     -DBUILD_WITH_KF=$BUILD_WITH_KF \
     -DBUILD_KF=OFF \
@@ -258,6 +259,7 @@ echo "Install Info.plist and app icon:"
 cp -R ${current_dir}/misc/Info.plist $BUNDLE/Contents/
 cp -R ${current_dir}/ico/mac_icon/*.icns $BUNDLE/Contents/Resources/
 /usr/libexec/PlistBuddy -c "Set :CFBundleShortVersionString $VERSION r$HEAD" "$BUNDLE/Contents/Info.plist"
+/usr/libexec/PlistBuddy -c "Set :LSMinimumSystemVersion 14.0.0" "$BUNDLE/Contents/Info.plist"
 
 ### add missing files ###############################################
 echo