bound log growth and reclaim ~52 GB of container disk

Caddy was rotating on implicit defaults (100MiB/keep 10/90d) that were not
holding -- 20 rotated files per stream and a 190-day-old .gz, 1.3 GB across
16 log streams. Made explicit at 10MiB/keep 3/7d.

Note roll_size et al are subdirectives of `output file`, NOT of `log`.
Getting that wrong does not degrade gracefully: Caddy refuses to start on a
bad config, so every site went down until it was corrected. Worth a
`caddy validate` gate before reload.

journald had no SystemMaxUse and had reached 4 GB, drifting toward its
10%-of-filesystem default (~190 GB on this root). Capped at 500M.

Both are safe to keep short because fluent-bit ships the journal and every
Caddy access log into Graylog -- though note its GELF output has been
erroring for days, which weakens that premise and wants investigating.

The larger find was unrelated to logs: 896 images totalling 59.6 GB with
75% unused (94 tags of greg-time-bot, 73 of fulfillr -- one per deploy) and
5.4 GB of dangling volumes, mostly 804 MB Nextcloud /var/www/html trees
orphaned by container recreations. Pruned to 22 images / 15.4 GB, and added
a weekly timer keeping 30 days so a rollback still needs no rebuild.

Also dropped the decommissioned 6379/tcp redis rule (nothing listening;
Immich's redis is on the shared podman network) and the orphaned nosql, s3
and searxng volume dirs.

Backup log exclusions turned out to be unnecessary: Gitea logs to console
so its log dirs are empty, Nextcloud already excludes its own, BookStack
mounts only uploads, and Caddy is not backed up.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

ansible/roles/podman/tasks/main.yml

@@ -2,6 +2,9 @@
 - import_tasks: firewall.yml
 - import_tasks: podman/podman.yml
 
+- import_tasks: podman/podman-prune.yml
+  tags: podman-prune
+
 # WEB SERVER: Caddy is the default and only web server
 # nginx has been completely replaced and removed