Witness sessions use format gt-witness-<rig> but categorizeSession was
parsing them as gt-<rig>-<type>, incorrectly setting Rig="witness".
This caused the mayor status line to count "witness" as a third rig.
Added special case to handle gt-witness-<rig> format before the generic
rig-level parsing. Also updated tests to cover both actual and legacy formats.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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