Adds failing unit tests for repl_fmt_jobid_range() covering contiguous
ranges, non-contiguous sub-ranges, multiple array bases, mixed array/
non-array ids, and a too-small output buffer (Requirement 4, AC 4.1-4.5).
The function itself is not yet implemented (task 1.2) - build fails at
link time with undefined reference to repl_fmt_jobid_range, confirming
the RED phase.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YAWMhfRJFnmmnG8h97yUDd
