Persist jump-host's Redis data across rebuilds (#106)

Companion to theta42/jump-host#18: that PR turns on Redis persistence
(AOF + RDB) at /data, but without a volume mount, persistence-within-the-
container is pointless -- docker rm -f (which every real rebuild uses,
per this repo's own documented docker-compose-v1 recreate quirk) throws
the container's whole filesystem away regardless. Adds jump-redis-data:/data,
matching proxy-data's existing role for the same package (lua-resty-auto-ssl
also relies on Redis persistence, via its own volume).

Verified: minted a jump-host API token, force-recreated the container,
confirmed the token still worked afterward.

Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>

docker-compose.yml

@@ -187,6 +187,7 @@ services:
     volumes:
       - ./config:/config:ro         # jump-secrets.js (written by ensure_config/bootstrap)
       - jump-data:/var/lib/jump-host  # generated host keys persist here
+      - jump-redis-data:/data         # Redis (sessions, OAuth state, API tokens) persists here
 
 networks:
   theta-net:
@@ -199,4 +200,5 @@ volumes:
   proxy-data:
   proxy-cache:
   proxy-logs:
-  jump-data:
+  jump-data:
+  jump-redis-data: