chore(githooks): refresh pre-commit (gitleaks protect fallback) + track reference-transaction

.githooks/pre-commit

@@ -9,10 +9,15 @@ git rev-parse --verify -q HEAD >/dev/null 2>&1 || exit 0   # root commit — all
 
 # Secret backstop (job7) — any branch, not just protected ones. Non-blocking
 # if gitleaks isn't installed; auto-discovers ./.gitleaks.toml (repo root).
+# gitleaks >= 8.19 scans the index with `git --staged`; older builds (Ubuntu's
+# 8.16 package) only know `protect --staged`, and `git` exits 1 there as an
+# unknown command — which would block every commit. Probe the subcommand first.
 if command -v gitleaks >/dev/null 2>&1; then
-  if ! gitleaks git --staged --no-banner >/dev/null 2>&1; then
+  gl_sub=git
+  gitleaks git --help >/dev/null 2>&1 || gl_sub=protect
+  if ! gitleaks "$gl_sub" --staged --no-banner >/dev/null 2>&1; then
     echo "gitflow pre-commit: BLOCKED — gitleaks found a secret in staged changes." >&2
-    echo "  Details: gitleaks git --staged --no-banner" >&2
+    echo "  Details: gitleaks $gl_sub --staged --no-banner" >&2
     echo "  Genuine false-positive? add an allowlist rule to .gitleaks.toml — never bypass with --no-verify." >&2
     exit 1
   fi

.githooks/reference-transaction

@@ -0,0 +1,15 @@
+#!/bin/sh
+# gitflow reference-transaction — generated by gitflow_init. Do not hand-edit.
+# Refuses deleting (or renaming) main / develop, whatever the
+# command. Mirrors gitflow_protected_base (lib/gitflow.sh).
+[ "$1" = prepared ] || exit 0
+while read -r _old new ref; do
+  case "$ref" in refs/heads/main|refs/heads/develop) ;; *) continue ;; esac
+  case "$new" in *[!0]*) continue ;; esac     # new value not all-zeros → an update, not a deletion
+  # Per-repo opt-out (a foreign clone): git config gitflow.protect false
+  [ "$(git config --bool --default true gitflow.protect)" = false ] && exit 0
+  echo "gitflow reference-transaction: BLOCKED — deleting '$ref', a protected base." >&2
+  echo "  main and develop are never deleted or renamed. A merged working branch: gitflow.sh delete <branch>" >&2
+  exit 1
+done
+exit 0