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

.gitea/runner/setup-workstation.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# Run as the existing deploy user on workstation. Never resets the working tree.
+set -euo pipefail
+here="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+repo="${HOMELAB_REPO:-/srv/homelab}"
+for tool in python3 git kubectl helm docker flock timeout; do
+  command -v "$tool" >/dev/null || { echo "Install missing dependency: $tool" >&2; exit 1; }
+done
+[ -d "$repo/.git" ] || { echo "Missing deploy checkout: $repo" >&2; exit 1; }
+[[ "$repo" =~ ^/[A-Za-z0-9_./-]+$ ]] || { echo 'Deploy path must be absolute and contain no whitespace' >&2; exit 1; }
+if [ "$(loginctl show-user "$USER" -p Linger --value)" != yes ]; then
+  echo "Run once: sudo loginctl enable-linger $USER" >&2
+  exit 1
+fi
+config="${XDG_CONFIG_HOME:-$HOME/.config}/homelab-deploy"
+mkdir -p "$config" "$HOME/.local/lib/homelab-deploy" "$HOME/.config/systemd/user"
+chmod 700 "$config"
+if [ ! -f "$config/environment" ]; then
+  context="$(kubectl config current-context)"
+  cluster_uid="$(kubectl get namespace kube-system -o jsonpath='{.metadata.uid}')"
+  printf 'HOMELAB_REPO=%s\nKUBE_CONTEXT=%s\nEXPECTED_CLUSTER_UID=%s\n' "$repo" "$context" "$cluster_uid" >"$config/environment"
+  chmod 600 "$config/environment"
+fi
+# Do not replace a dispatcher while an existing deploy uses it.
+if systemctl --user list-units 'homelab-deploy@*' --state=running --no-legend | grep -q .; then
+  echo 'An existing deploy is running; wait before updating the controller' >&2
+  exit 1
+fi
+install -m 0755 "$here/../workflows/deploy-controller.py" "$HOME/.local/lib/homelab-deploy/controller.py"
+install -m 0644 "$here/homelab-deploy@.service" "$HOME/.config/systemd/user/homelab-deploy@.service"
+systemctl --user daemon-reload
+echo 'Controller ready. Run a checked main SHA in full mode for the initial baseline.'