Update dev to 3.13.1

[marionbarker]

Purpose

Collect updates to dev branch prior to merge into dev.

When ready and approved, this PR will be merged into dev with version number 3.13.1

The Details section of this PR will be updated with each commit added to this PR.

Details

• bump version number to 3.13.1
• update runners to macos-26, build with Xcode 26.2
  • This removes the warning that SDK 18 can not be used with TestFlight in April 2026
• update to use Node.js 24 for github actions
  • There are 3 helper repositories that used Node.js 20
  • These have all been updated to use Node.js 24 and the specific tags in the yml files were updated to point to the updated versions
  • This removes the warnings in the action annotations that Node.js 20
• fix the NUKE_CERTS variables to be case insensitive PR fix NUKE_CERT variables to be case insensitive #424

Test

Prior to uploading updates to LoopKit/LoopWorkspace, confirm each modification can be built.

Specific tests:

The Node.js 24 success is shown here:

• ✅ with 3.13.1, no warning messages: https://github.com/docs-test/LoopWorkspace/actions/runs/23494808846
• compared to 3.13.1, multiple Node.js 20 warning messages: https://github.com/docs-test/LoopWorkspace/actions/runs/23495551898