docs: add Gitea runner installation

scripts/install-gitea-runner.sh

@@ -0,0 +1,98 @@
+#!/usr/bin/env bash
+# Install and register a repository-scoped Gitea Actions runner on a dedicated Linux CI host.
+# This script must be run on the CI host, not on the Gitea application server.
+
+set -Eeuo pipefail
+
+readonly RUNNER_VERSION="${RUNNER_VERSION:-0.2.11}"
+readonly RUNNER_USER="${RUNNER_USER:-gitea-runner}"
+readonly RUNNER_HOME="${RUNNER_HOME:-/opt/gitea-runner}"
+readonly INSTANCE_URL="${INSTANCE_URL:-https://git.mozdit.hu}"
+readonly RUNNER_NAME="${RUNNER_NAME:-mozdit-ci-01}"
+readonly RUNNER_LABELS="${RUNNER_LABELS:-ubuntu-latest:host}"
+
+fail() {
+  printf 'HIBA: %s\n' "$*" >&2
+  exit 1
+}
+
+require_command() {
+  command -v "$1" >/dev/null 2>&1 || fail "Hiányzó parancs: $1"
+}
+
+if [[ "${EUID}" -ne 0 ]]; then
+  fail "Futtasd sudo-val: sudo ./scripts/install-gitea-runner.sh"
+fi
+
+require_command curl
+require_command docker
+require_command node
+require_command npm
+
+docker info >/dev/null 2>&1 || fail "A Docker daemon nem érhető el. Indítsd el, majd futtasd újra a scriptet."
+docker compose version >/dev/null 2>&1 || fail "Hiányzik a Docker Compose v2 (docker compose)."
+
+case "$(uname -m)" in
+  x86_64) runner_arch="amd64" ;;
+  aarch64|arm64) runner_arch="arm64" ;;
+  *) fail "Nem támogatott CPU-architektúra: $(uname -m)" ;;
+esac
+
+readonly RUNNER_ARCH="${runner_arch}"
+readonly RUNNER_URL="https://dl.gitea.com/gitea-runner/${RUNNER_VERSION}/act_runner-${RUNNER_VERSION}-linux-${RUNNER_ARCH}"
+
+if ! id -u "${RUNNER_USER}" >/dev/null 2>&1; then
+  useradd --system --create-home --home-dir "${RUNNER_HOME}" --shell /usr/sbin/nologin "${RUNNER_USER}"
+fi
+
+usermod -aG docker "${RUNNER_USER}"
+install -d -o "${RUNNER_USER}" -g "${RUNNER_USER}" -m 0750 "${RUNNER_HOME}"
+
+tmp_binary="$(mktemp)"
+trap 'rm -f "${tmp_binary}"' EXIT
+curl --fail --location --retry 3 --output "${tmp_binary}" "${RUNNER_URL}"
+install -o root -g root -m 0755 "${tmp_binary}" "${RUNNER_HOME}/act_runner"
+
+"${RUNNER_HOME}/act_runner" --version
+
+if [[ ! -f "${RUNNER_HOME}/.runner" ]]; then
+  if [[ -z "${GITEA_RUNNER_REGISTRATION_TOKEN:-}" ]]; then
+    read -r -s -p "Gitea runner regisztrációs token: " GITEA_RUNNER_REGISTRATION_TOKEN
+    printf '\n'
+  fi
+  [[ -n "${GITEA_RUNNER_REGISTRATION_TOKEN}" ]] || fail "Üres regisztrációs token."
+
+  # The token is intentionally neither written to disk nor printed by this script.
+  runuser -u "${RUNNER_USER}" -- "${RUNNER_HOME}/act_runner" register --no-interactive \
+    --instance "${INSTANCE_URL}" \
+    --token "${GITEA_RUNNER_REGISTRATION_TOKEN}" \
+    --name "${RUNNER_NAME}" \
+    --labels "${RUNNER_LABELS}"
+else
+  printf 'A runner már regisztrálva van, a regisztráció kihagyva.\n'
+fi
+
+install -m 0644 /dev/stdin /etc/systemd/system/gitea-act-runner.service <<EOF
+[Unit]
+Description=Gitea Actions Runner (${RUNNER_NAME})
+After=network-online.target docker.service
+Wants=network-online.target
+
+[Service]
+User=${RUNNER_USER}
+WorkingDirectory=${RUNNER_HOME}
+ExecStart=${RUNNER_HOME}/act_runner daemon
+Restart=always
+RestartSec=5
+NoNewPrivileges=true
+PrivateTmp=true
+
+[Install]
+WantedBy=multi-user.target
+EOF
+
+systemctl daemon-reload
+systemctl enable --now gitea-act-runner.service
+systemctl --no-pager --full status gitea-act-runner.service
+
+printf '\nKész. Ellenőrizd a Gitea felületén: Settings → Actions → Runners; az állapotnak Idle-nak kell lennie.\n'