The rigs/ directory was created by gt install but never used by
gt rig add, which puts rigs at the town root. Rather than restructure
the entire codebase to use rigs/, we remove the unused directory.
Flat structure is fine - similar to Android top-level layout with
100+ subprojects. Rigs at root works well and avoids a breaking change.
Closes#74🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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