- Fix potential crash when C4::Context->userenv returns undef:
use the established ternary guard pattern used throughout other
TT plugins (AuthorisedValues, Branches, Desks, etc.)
- Remove dead second argument passed to GetLettersAvailableForALibrary,
which only accepts one argument; the group_by/columns/order_by
hashref was silently dropped
- Fix typo "librries" -> "libraries" in GetByModuleForLibrary POD
- Update POD example to use 'add_message' module matching actual usage
- Add test coverage for GetByModuleForLibrary, verifying that a user
logged in to a branch sees branch-specific and all-libraries notices,
while users at other branches see only all-libraries notices
Signed-off-by: Martin Renvoize <martin.renvoize@openfifth.co.uk>
b18fbab806