## Description
Fixed broken documentation link in the air-gapped setup guide that was
pointing to a non-existent `/Pro/#activation` page (returning 404).
Updated to the correct `/Paid-Offerings/#activating-your-license` URL
which returns 200 OK.
## Changes Made
- Updated link in `frontend/src/core/data/useTranslatedToolRegistry.tsx`
(line 838)
- Changed from `https://docs.stirlingpdf.com/Pro/#activation` to
`https://docs.stirlingpdf.com/Paid-Offerings/#activating-your-license`
## Testing
- Verified old link returns 404
- Verified new link returns 200 and has activation section
- Link now correctly points to the "Activating Your License" section of
the Paid Offerings documentation
## Related Issue
Resolves#5088
## Checklist
- [x] Code follows project style guidelines
- [x] Changes are limited to fixing the broken link only (atomic commit)
- [x] Link has been manually tested and verified working
