feat: admin audit logging across all admin actions

- AdminLogger: JSON-lines → /var/log/xamxam.log (prod) / storage/logs/admin.log (dev)
  + best-effort DB mirror to admin_audit_log table
- DB: admin_audit_log table, share_links.is_archived column
- ShareLink: archive() replaces delete(), toggleActive() returns new state,
  listActive()/listArchived() split, validateLink blocks archived slugs
- All action handlers wired: publish, unpublish, visibility, delete, csv/db export,
  tfe add/edit, tags, pages, apropos, form-help, access-request, maintenance,
  settings (formulaire toggles, objet types, smtp update), smtp-test
- acces.php: archive button replaces delete; collapsible archived links section
- setup-server.sh: provision /var/log/xamxam.log (www-data:xamxam 640)

scripts/setup-server.sh

@@ -88,6 +88,14 @@ chown -R "$WEB_USER:$APP_GROUP" "$APP_DIR/storage/cache"
 chmod -R 2775 "$APP_DIR/storage/cache"
 ok "Cache dirs: created and owned by $WEB_USER:$APP_GROUP"
 
+# ── 8. Provision /var/log/xamxam.log ─────────────────────────────────────────
+if [ ! -f /var/log/xamxam.log ]; then
+    touch /var/log/xamxam.log
+fi
+chown "$WEB_USER:$APP_GROUP" /var/log/xamxam.log
+chmod 640 /var/log/xamxam.log
+ok "/var/log/xamxam.log: owned by $WEB_USER:$APP_GROUP (640)"
+
 printf "\n"
 ok "Setup complete."
 printf "\nNext steps:\n"