fix: standalone on ubuntu (#865)

* Standalone on ubuntu

* fix: use port 3043 for Caddy, disable rooms, remove dead Caddyfile

- Caddy mapped to host port 3043 instead of 80/443 to avoid conflicts
- FEATURE_ROOMS=false in standalone web service
- Removed scripts/standalone/Caddyfile (dead code on this branch)
- Updated all URLs, port checks, docs to reference :3043

---------

Co-authored-by: Igor Loskutov <igor.loskutoff@gmail.com>

scripts/install-docker-ubuntu.sh

@@ -0,0 +1,87 @@
+#!/usr/bin/env bash
+#
+# Install Docker Engine + Compose plugin on Ubuntu.
+# Ubuntu's default repos don't include docker-compose-plugin, so we add Docker's official repo.
+#
+# Usage:
+#   ./scripts/install-docker-ubuntu.sh
+#
+# Requires: root or sudo
+#
+set -euo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+
+# --- Colors ---
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+CYAN='\033[0;36m'
+NC='\033[0m'
+
+info()  { echo -e "${CYAN}==>${NC} $*"; }
+ok()    { echo -e "${GREEN}  ✓${NC} $*"; }
+warn()  { echo -e "${YELLOW}  !${NC} $*"; }
+err()   { echo -e "${RED}  ✗${NC} $*" >&2; }
+
+# Use sudo if available and not root; otherwise run directly
+if [[ $(id -u) -eq 0 ]]; then
+    MAYBE_SUDO=""
+elif command -v sudo &>/dev/null; then
+    MAYBE_SUDO="sudo "
+else
+    err "Need root. Run as root or install sudo: apt install sudo"
+    exit 1
+fi
+
+# Check Ubuntu
+if [[ ! -f /etc/os-release ]]; then
+    err "Cannot detect OS. This script is for Ubuntu."
+    exit 1
+fi
+source /etc/os-release
+if [[ "${ID:-}" != "ubuntu" ]] && [[ "${ID_LIKE:-}" != *"ubuntu"* ]]; then
+    err "This script is for Ubuntu. Detected: ${ID:-unknown}"
+    exit 1
+fi
+
+info "Adding Docker's official repository..."
+${MAYBE_SUDO}apt update
+${MAYBE_SUDO}apt install -y ca-certificates curl
+${MAYBE_SUDO}install -m 0755 -d /etc/apt/keyrings
+${MAYBE_SUDO}rm -f /etc/apt/sources.list.d/docker.list /etc/apt/sources.list.d/docker.sources
+curl -fsSL https://download.docker.com/linux/ubuntu/gpg | ${MAYBE_SUDO}tee /etc/apt/keyrings/docker.asc > /dev/null
+${MAYBE_SUDO}chmod a+r /etc/apt/keyrings/docker.asc
+CODENAME="$(. /etc/os-release && echo "${UBUNTU_CODENAME:-${VERSION_CODENAME:-}}")"
+[[ -z "$CODENAME" ]] && { err "Could not detect Ubuntu version codename."; exit 1; }
+${MAYBE_SUDO}tee /etc/apt/sources.list.d/docker.sources > /dev/null <<EOF
+Types: deb
+URIs: https://download.docker.com/linux/ubuntu
+Suites: ${CODENAME}
+Components: stable
+Signed-By: /etc/apt/keyrings/docker.asc
+EOF
+
+info "Installing Docker Engine and Compose plugin..."
+${MAYBE_SUDO}apt update
+${MAYBE_SUDO}apt install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
+
+if [[ -d /run/systemd/system ]]; then
+    info "Enabling and starting Docker..."
+    ${MAYBE_SUDO}systemctl enable --now docker
+else
+    err "No systemd. This script requires Ubuntu with systemd (e.g. DigitalOcean droplet)."
+    exit 1
+fi
+
+DOCKER_USER="${SUDO_USER:-${USER:-root}}"
+if [[ "$DOCKER_USER" != "root" ]]; then
+    info "Adding $DOCKER_USER to docker group..."
+    ${MAYBE_SUDO}usermod -aG docker "$DOCKER_USER"
+fi
+
+ok "Docker installed successfully."
+echo ""
+echo "  Log out and back in (or run: newgrp docker) so the group change takes effect."
+echo "  Then verify with: docker compose version"
+echo ""