Make NODE_BINARY discovery nvm-friendly for CI

Add nvm support to packages/app/ios/.xcode.env and ensure CI writes a local ios/.xcode.env.local with the actual node path (using which node) so Xcode script phases can find Node in nvm environments. Remove the previously committed hardcoded .xcode.env.local and drop a debug fastlane test step from .gitlab-ci.yml. This replaces the static /usr/local/bin/node path with dynamic discovery to avoid CI/Xcode build failures on runners using nvm.
1 job for main in 8 minutes and 25 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
failed #127618
studio triggered
ci-build

00:08:25

 
Name Stage Failure
failed
ci-build Build
  output: [ null, null, null ],
pid: 99885,
stdout: null,
stderr: null
}

Node.js v18.20.4
Cleaning up project directory and file based variables
ERROR: Job failed: exit status 1