refactor(ci): use native runner and durable incremental deploys

.gitea/runner/setup-runner.sh

@@ -0,0 +1,48 @@
+#!/usr/bin/env bash
+# Native host runner, with pinned user-space tools and no extra CI images.
+set -euo pipefail
+here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+[ "$(id -u)" -eq 0 ] || { echo 'Run with sudo on the runner host' >&2; exit 1; }
+for tool in docker curl python3 git tar xz flock runuser systemctl; do
+  command -v "$tool" >/dev/null || { echo "Install missing prerequisite: $tool" >&2; exit 1; }
+done
+docker info >/dev/null
+docker compose version >/dev/null
+docker buildx version >/dev/null
+id gitea-runner >/dev/null 2>&1 || useradd --system --create-home --home-dir /var/lib/gitea-runner --shell /usr/bin/bash gitea-runner
+# Reuse the established service account and runner registration.
+runner_home="$(getent passwd gitea-runner | cut -d: -f6)"
+[ "$runner_home" = /var/lib/gitea-runner ] || { echo 'Unexpected runner home; inspect the existing service first' >&2; exit 1; }
+runuser -u gitea-runner -- docker info >/dev/null || { echo "The runner user needs access to Docker before setup" >&2; exit 1; }
+command -v gitea-runner >/dev/null || { echo 'Install gitea-runner 3.0.2 at /usr/local/bin/gitea-runner first' >&2; exit 1; }
+mkdir -p /etc/gitea-runner
+stamp="$(date -u +%Y%m%dT%H%M%SZ)"
+for existing in /etc/gitea-runner/config.yaml /etc/systemd/system/gitea-runner.service; do
+  [ ! -f "$existing" ] || cp -p "$existing" "$existing.before-$stamp"
+done
+scratch="$(mktemp -d)"
+trap 'rm -rf "$scratch"' EXIT
+chmod 755 "$scratch"
+install -m 0644 "$here/../workflows/install-ci-tools.sh" "$here/../workflows/tool-versions.env" "$scratch/"
+runuser -u gitea-runner -- bash "$scratch/install-ci-tools.sh"
+install -m 0644 "$here/config.yaml" /etc/gitea-runner/config.yaml
+python3 - <<'PYLABELS'
+import json
+from pathlib import Path
+registration = Path('/var/lib/gitea-runner/.runner')
+if registration.exists():
+    labels = json.loads(registration.read_text()).get('labels', [])
+    labels = [label for label in labels if isinstance(label, str) and label.split(':')[0] != 'homelab']
+    labels.append('homelab:host')
+    config = Path('/etc/gitea-runner/config.yaml')
+    config.write_text(config.read_text().replace('    - homelab:host', '\n'.join('    - ' + json.dumps(label) for label in labels)))
+PYLABELS
+install -m 0644 "$here/gitea-runner.service" /etc/systemd/system/gitea-runner.service
+if [ ! -f /var/lib/gitea-runner/.runner ]; then
+  echo 'Register once as gitea-runner with homelab:host before starting the service.'
+  exit 0
+fi
+systemctl daemon-reload
+systemctl enable --now gitea-runner.service
+systemctl restart gitea-runner.service
+echo "Runner ready. Configuration backups: *.before-$stamp"