The agent-beads-exist check was hardcoding '/mayor/rig' suffix when
constructing the beads path, but routes.jsonl can contain paths like
'my-saas' without this suffix.
This caused the check to look for beads in the wrong location:
- Expected: <town>/<route-path>/.beads (e.g., ~/gt/my-saas/.beads)
- Actual: <town>/<rig>/mayor/rig/.beads (e.g., ~/gt/my-saas/mayor/rig/.beads)
The fix stores the full route path and uses it directly when creating
the beads client, instead of reconstructing an assumed path structure.
Fixes agent beads not being found when routes use simple rig names.
aaee7fed40