Instead of changing the convoy ID format, register the hq-cv- prefix
as a valid route pointing to town beads. This preserves the semantic
meaning of convoy IDs (hq-cv-xxxxx) while fixing the prefix mismatch.
Changes:
- Register hq-cv- prefix during gt install
- Add doctor check and fix for missing convoy route
- Update routes_check tests for both hq- and hq-cv- routes
Fixes: gt-4nmfh
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>