chore(ci): bootstrap CI + hooks

Squash-merge bootstrap-cicd into integration

scripts/commitlint-hook

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+MSG_FILE="${1:-.git/COMMIT_EDITMSG}"
+
+# Run commitlint inside the CI container against the commit message file
+docker compose -f docker/ci.compose.yml run --rm \
+  -e IN_CI_CONTAINER=1 \
+  ci bash -lc "commitlint --edit ${MSG_FILE}"
+