Control characters (newlines, tabs) in item titles corrupted git log
output. Now strips control chars and truncates to 50 chars.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Locks the singular vs plural transition (1 minute ago vs 2 minutes
ago) and each bucket boundary (59→60s minutes, 3599→3600s hours,
86400→86400×2 days, etc.) so future tweaks can't silently regress
the user-facing labels.
Reads .relicario/last_backup (written by cmd_backup_export). Format:
'never' for fresh vaults, '4 days ago' otherwise. Closes the
'is my backup stale?' question without leaving the terminal.
