chore(workflows/build): use macos-26

Author: XuehaiPan

.github/workflows/build.yml

@@ -158,9 +158,9 @@ jobs:
             target: { runner: macos-latest, archs: "arm64_iphoneos" }
           # iOS Simulator
           - python-version: "3.13"
-            target: { runner: macos-latest, archs: "arm64_iphonesimulator" }
+            target: { runner: macos-26, archs: "arm64_iphonesimulator" }
           - python-version: "3.14"
-            target: { runner: macos-latest, archs: "arm64_iphonesimulator" }
+            target: { runner: macos-26, archs: "arm64_iphonesimulator" }
           # Android
           - python-version: "3.13"
             target: { runner: ubuntu-latest, archs: "arm64_v8a" }