fix(syslog): word its audit actions, list its tables for backups, mark its page top-level, reach its modules as loaded (#5999)

- Audit: syslog.source_* worded, and a Syslog filter area.
- Backups keep syslog_sources (added, named, ignored; what it last sent
  isn't compared) and leave syslog_lines out, as logs.
- The integration test reaches the plugin as loaded (#5775), so its
  tables aren't defined twice; ruff E741.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

steward/audit/service.py

@@ -198,6 +198,11 @@ ACTIONS = {
     "prometheus.template_created": "added Prometheus widget template",
     "prometheus.template_updated": "changed Prometheus widget template",
     "prometheus.template_deleted": "deleted Prometheus widget template",
+    "syslog.source_added": "added syslog source",
+    "syslog.source_updated": "changed syslog source",
+    "syslog.source_removed": "removed syslog source",
+    "syslog.source_ignored": "ignored syslog sender",
+    "syslog.source_offered": "offered again syslog sender",
     "backup.made": "sent a backup",
     "backup.failed": "tried to send a backup, which failed:",
     "backup.restored": "restored Steward from a backup",
@@ -210,7 +215,7 @@ AREAS = (("auth.", "Sign-ins"), ("account.", "Accounts"), ("user.", "Users"), ("
          ("ansible.run", "Playbook runs"), ("ansible.", "Ansible (all)"),
          ("settings.", "Settings"), ("plugin.", "Plugins"), ("api_token.", "AI access"),
          ("docker.", "Docker"), ("snmp.", "SNMP"), ("prometheus.", "Prometheus"),
-         ("backup.", "Backups"))
+         ("syslog.", "Syslog"), ("backup.", "Backups"))
 
 
 def action_text(action: str) -> str: