chore: enforce standard branch release workflow

scripts/new-branch.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+BASE_REF="${BASE_REF:-}"
+
+usage() {
+  cat <<'EOF'
+Usage:
+  bash scripts/new-branch.sh <branch-name>
+
+Creates a new development branch from the latest origin/main.
+
+Environment:
+  BASE_REF     Base ref to create from. Defaults to origin/main when available.
+EOF
+}
+
+if [[ "${1:-}" == "-h" || "${1:-}" == "--help" || $# -ne 1 ]]; then
+  usage
+  [[ $# -eq 1 ]] && exit 0 || exit 1
+fi
+
+branch="$1"
+
+if [[ -n "$(git -C "${ROOT}" status --porcelain=v1 --untracked-files=all)" ]]; then
+  echo "New branch check failed: current worktree is not clean." >&2
+  git -C "${ROOT}" status --short --untracked-files=all >&2
+  exit 1
+fi
+
+if git -C "${ROOT}" remote get-url origin >/dev/null 2>&1; then
+  git -C "${ROOT}" fetch origin --prune
+fi
+
+if [[ -z "${BASE_REF}" ]]; then
+  for candidate in origin/main origin/master main master; do
+    if git -C "${ROOT}" rev-parse --verify --quiet "${candidate}" >/dev/null; then
+      BASE_REF="${candidate}"
+      break
+    fi
+  done
+fi
+
+git -C "${ROOT}" rev-parse --verify --quiet "${BASE_REF}" >/dev/null || {
+  echo "New branch check failed: base ref not found: ${BASE_REF}" >&2
+  exit 1
+}
+
+git -C "${ROOT}" switch -c "${branch}" "${BASE_REF}"
+echo "Created ${branch} from ${BASE_REF}."