docs: note Ubuntu Resolute exceptional behavior in NOTES.md

Agent-Logs-Url: https://github.com/devcontainers/features/sessions/8983ff12-365e-49de-bd65-47614caf8539

Co-authored-by: Kaniska244 <186041440+Kaniska244@users.noreply.github.com>

Author: Copilot

src/docker-in-docker/NOTES.md

@@ -15,4 +15,6 @@ This Feature should work on recent versions of Debian/Ubuntu-based distributions
 
 Debian Trixie (13) does not include moby-cli and related system packages, so the feature cannot install with "moby": "true". To use this feature on Trixie, please set "moby": "false" or choose a different base image (for example, Ubuntu 24.04).
 
+Ubuntu 26.04 (Resolute) does not currently have moby packages available, so the feature cannot install with "moby": "true". To use this feature on Resolute, please set "moby": "false". Additionally, the kernel on Ubuntu 26.04 no longer supports legacy iptables NAT tables, so the feature automatically falls back to `iptables-nft` when `iptables-legacy` is not functional.
+
 `bash` is required to execute the `install.sh` script.