ci: build the backend image in its own workflow and shorten the panel offer wait [CI]

ci/restore-linux-dependencies.sh

@@ -2,8 +2,8 @@
 # Resolve Backend and Agent dependencies once before Linux build tasks start.
 set -euo pipefail
 
-mode="${1:?usage: restore-linux-dependencies.sh <dev|release|agent>}"
-case "$mode" in dev|release|agent) ;; *) exit 2 ;; esac
+mode="${1:?usage: restore-linux-dependencies.sh <dev-backend|dev-agent|release|agent>}"
+case "$mode" in dev-backend|dev-agent|release|agent) ;; *) exit 2 ;; esac
 root="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 work="$root/.release/linux-restore"
 base_home="/home/justme/woodpecker/buildah-home/linux-agent"
@@ -24,15 +24,15 @@ trap cleanup EXIT
 source "$root/ci/version.sh"
 export NUGET_PACKAGES="${NUGET_PACKAGES:-/home/justme/woodpecker/cache/nuget/packages}"
 mkdir -p "$NUGET_PACKAGES"
-if [[ "$mode" == dev ]]; then
+if [[ "$mode" == dev-* ]]; then
   [[ "${CI_PIPELINE_EVENT:-}" == push && "${CI_COMMIT_BRANCH:-}" == main && "${CI_COMMIT_MESSAGE:-}" == *'[CI]'* ]] || exit 2
 else
   [[ "${CI_COMMIT_TAG:-}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9A-Za-z.-]+)?$ ]] || exit 2
 fi
 moshiro_apply_version
 
-if [[ "$mode" == dev || "$mode" == release ]]; then
-  if [[ "$mode" == dev ]]; then
+if [[ "$mode" == dev-backend || "$mode" == release ]]; then
+  if [[ "$mode" == dev-backend ]]; then
     backend_rids=(linux-x64)
   else
     backend_rids=(linux-x64 linux-arm64)
@@ -52,7 +52,7 @@ if [[ "$mode" == dev || "$mode" == release ]]; then
   done
 fi
 
-if [[ "$mode" == dev || "$mode" == agent ]]; then
+if [[ "$mode" == dev-agent || "$mode" == agent ]]; then
   [[ "${CI_COMMIT_SHA:-}" =~ ^[0-9a-fA-F]{40}$ ]] || { echo 'CI_COMMIT_SHA must be a full commit SHA' >&2; exit 2; }
   mkdir -p "$work" "$base_home"
   exec 9> "$base_home/.lock"