Two follow-ups on top of helix4u's slash-command sync hardening:
- Only suppress exceptions that are actually Discord 429 rate limits
(discord.RateLimited, HTTPException with status 429, or a clearly
rate-limit-named duck type). Arbitrary failures that happen to expose
a retry_after attribute now re-raise to the outer handler instead of
silently swallowing a cooldown.
- Move the sync-state JSON under $HERMES_HOME/gateway/ so the home root
stops collecting ad-hoc runtime files.
Added a test verifying unrelated exceptions don't get misclassified as
rate limits.
5a3cadf6eb