feat(svc-runners): add the logic to have x numbers of runners self hosted ad connected to GIthub, allowing to have 20 runners from gh + x self hosted

scripts/github/split_runner_apps.sh

@@ -0,0 +1,43 @@
+#!/usr/bin/env bash
+# Splits a JSON array of app IDs proportionally between GitHub-hosted and
+# self-hosted CI runners.
+#
+# When CI_SELF_HOSTED_RUNNER_COUNT is 0 or unset, all apps are assigned to
+# the GitHub-hosted batch and the self-hosted batch is empty — CI behaves
+# exactly as before with no self-hosted runners registered.
+#
+# The split ratio mirrors the relative throughput of each runner pool:
+#   github_count = floor(total × GITHUB_QUOTA / (GITHUB_QUOTA + SELF_HOSTED_COUNT))
+#
+# Inputs (environment variables):
+#   APPS_JSON                    JSON array of app IDs from the discover step
+#   CI_SELF_HOSTED_RUNNER_COUNT  self-hosted runner instance count (default: 0)
+#
+# Outputs (appended to $GITHUB_OUTPUT):
+#   apps_github       JSON array routed to GitHub-hosted runners
+#   apps_self_hosted  JSON array routed to self-hosted runners ([] when disabled)
+set -euo pipefail
+
+APPS_JSON="${APPS_JSON:-[]}"
+SELF_HOSTED_COUNT="${CI_SELF_HOSTED_RUNNER_COUNT:-0}"
+GITHUB_QUOTA=20
+
+if [[ "${SELF_HOSTED_COUNT}" -le 0 ]]; then
+	echo "apps_github=${APPS_JSON}" >>"${GITHUB_OUTPUT}"
+	echo "apps_self_hosted=[]" >>"${GITHUB_OUTPUT}"
+	total="$(echo "${APPS_JSON}" | jq 'length')"
+	echo "=== Runner split: all ${total} apps → GitHub-hosted (self-hosted disabled) ==="
+	exit 0
+fi
+
+total="$(echo "${APPS_JSON}" | jq 'length')"
+github_count=$((total * GITHUB_QUOTA / (GITHUB_QUOTA + SELF_HOSTED_COUNT)))
+self_count=$((total - github_count))
+
+apps_github="$(echo "${APPS_JSON}" | jq -c ".[0:${github_count}]")"
+apps_self="$(echo "${APPS_JSON}" | jq -c ".[${github_count}:]")"
+
+echo "apps_github=${apps_github}" >>"${GITHUB_OUTPUT}"
+echo "apps_self_hosted=${apps_self}" >>"${GITHUB_OUTPUT}"
+
+echo "=== Runner split: ${github_count} apps → GitHub-hosted, ${self_count} apps → self-hosted (${SELF_HOSTED_COUNT} runners) ==="