`Failed to set localization.language to 'en-GB'` during first time setup

[benfrancis]

STR:

• Local build of WebThings Gateway master branch on macOS
• npm start
• Skip tunnel setup

Expected:

• Gateway starts successfully

Actual:

• Gateway fails to redirect away from tunnel setup page, see error on command line:

2025-12-18 16:05:08.882 ERROR : Failed to set localization.language to 'en-GB'

(I'm not sure where it gets this locale from, so may not reproduce everywhere)

Didn't reproduce on Ubuntu Linux for me.

[benfrancis]

Manually navigating to /things works, but root still serves tunnel setup page.