Add setup.sh for one-command server install

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

setup.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+REPO_URL="https://github.com/SantosFC/chamado-health.git"
+INSTALL_DIR="${HOME}/src/chamado-health"
+CONFIG_FILE="${HOME}/.config/chamado-health"
+
+if [[ -z "${HEALTHCHECK_URL:-}" ]]; then
+    read -rp "HEALTHCHECK_URL: " HEALTHCHECK_URL
+fi
+
+if [[ -d "${INSTALL_DIR}/.git" ]]; then
+    git -C "${INSTALL_DIR}" pull --ff-only
+else
+    git clone "${REPO_URL}" "${INSTALL_DIR}"
+fi
+
+echo "HEALTHCHECK_URL=${HEALTHCHECK_URL}" > "${CONFIG_FILE}"
+echo "Config saved to ${CONFIG_FILE}."
+
+bash "${INSTALL_DIR}/install_systemd.sh"
+
+loginctl enable-linger
+echo "Linger enabled — timer runs even without active session."