Upgrade to macOS 26

macos-latest does not target the latest macOS (26), so it has SDK-related issues.

Author: hwangsihu

.github/workflows/ios.yml

@@ -19,7 +19,7 @@ jobs:
             cmakearch: x86_64
             cmakesysroot: iphonesimulator
 
-    runs-on: macos-latest
+    runs-on: macos-26
 
     steps:
     - name: Checkout
@@ -62,7 +62,7 @@ jobs:
   lipo:
     needs: build
 
-    runs-on: macos-latest
+    runs-on: macos-26
 
     steps:
     - name: Checkout