build: link libghostty-vt on Apple hosts with native linker

Replaces: https://github.com/ghostty-org/ghostty/pull/13427

Zig's Mach-O linker does not emit LC_ENCRYPTION_INFO_64 for physical
iOS dylibs. This allows libghostty-vt to build successfully but causes
frameworks containing it to fail App Store validation.

I think it'd be cleaner to always just build Apple targets on Apple hosts
with the native linker. We don't need to rely on Zig being correct and 
this helps ensure compatibility for details like this.

.github/workflows/test.yml

@@ -618,7 +618,23 @@ jobs:
   build-libghostty-vt-macos:
     strategy:
       matrix:
-        target: [aarch64-macos, x86_64-macos, aarch64-ios]
+        include:
+          - target: aarch64-macos
+            platform: 1
+            arch: arm64
+            expect_encryption: false
+          - target: x86_64-macos
+            platform: 1
+            arch: x86_64
+            expect_encryption: false
+          - target: aarch64-ios
+            platform: 2
+            arch: arm64
+            expect_encryption: true
+          - target: aarch64-ios-simulator
+            platform: 7
+            arch: arm64
+            expect_encryption: false
     runs-on: namespace-profile-ghostty-macos-tahoe
     needs: test
     env:
@@ -653,6 +669,14 @@ jobs:
           nix develop -c zig build -Demit-lib-vt \
             -Dtarget=${{ matrix.target }}
 
+      - name: Verify Apple dylib
+        run: |
+          nix develop -c nu .github/scripts/check-apple-libghostty-vt.nu \
+            zig-out/lib/libghostty-vt.dylib \
+            --expect-platform ${{ matrix.platform }} \
+            --expect-arch ${{ matrix.arch }} \
+            ${{ matrix.expect_encryption && '--expect-encryption' || '' }}
+
   # lib-vt requires the Android NDK for Android builds
   build-libghostty-vt-android:
     strategy: