ci(ios): use Tahoe runner for Xcode 26.2 GM

Sequoia-stable has Xcode 16.4 which has linker issues. Tahoe runner
should have Xcode 26.2 GM (latest stable). The grep -iv beta filter
will skip any beta Xcode if both are installed.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: Claude

.github/workflows/ios-release.yml

@@ -12,7 +12,7 @@ concurrency:
 jobs:
   release:
     name: Build & Upload to TestFlight
-    runs-on: nscloud-macos-sequoia-stable-arm64-6x14
+    runs-on: nscloud-macos-tahoe-arm64-6x14
     timeout-minutes: 60
     steps:
       - uses: actions/checkout@v4