logs: standardise log filenames to xamxam-{service}-{date}.log

app/storage/README.md

@@ -24,7 +24,7 @@ just migrate        # run pending migrations
 | `schema.sql` | Full, fully-migrated schema + seed data (regenerated from the local DB) |
 | `backups/` | `just backup-snapshot` hot-backups (`*.db.gz`) |
 | `cache/` | Runtime cache (rate limits, etc.) |
-| `logs/` | Runtime logs (admin, audit) — **outside the webroot** |
+| `logs/` | Dev-only runtime logs (cli-server); production logs live in `/var/log/xamxam/` |
 | `covers/` | Cover images |
 | `theses/`, `tfe/`, `tmp/` | Uploaded files / staging |