trust-dns: bump StartLimitBurst so systemd doesnt abort the service too early

modules/services/trust-dns/default.nix

@@ -187,7 +187,11 @@ in
           User = "trust-dns";
           Group = "trust-dns";
           wantedBy = lib.mkForce [];
+          # there can be a lot of restarts as interfaces toggle,
+          # particularly around the DHCP/NetworkManager stuff.
+          StartLimitBurst = 60;
         };
+        # trust-dns.unitConfig.StartLimitIntervalSec = 60;
       }
       (lib.mapAttrs'
         (flavor: instanceConfig: {

modules/services/trust-dns/trust-dns-nmhook

@@ -108,11 +108,11 @@ def apply_zone(nm_config: NmConfig, ops: Ops) -> None:
         # formatting preference: when these configs are `cat`d together, empty-line separators help distinguish
         specialized_config = '\n' + specialized_config
 
-    # TODO: i'm not sure how this behaves in the presence of multiple interfaces.
-    # do i want to persist config-per-interface, and then merge them, on every change?
     conn_config_path = f"{DHCP_CONFIGS}/{nm_config.conn_id}.toml"
     ops.makedirs(DHCP_CONFIGS)
     ops.write_file(conn_config_path, specialized_config)
+    # TODO: don't restart if the merged config is expected to be the same;
+    # restarts are costly, especially since they dump the cache!
     ops.exec_([
         "systemctl",
         "restart",