chore: import upstream snapshot with attribution

scripts/codex/install-global-git-hooks.sh

@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# Install ECC git safety hooks globally via core.hooksPath.
+# Usage:
+#   ./scripts/codex/install-global-git-hooks.sh
+#   ./scripts/codex/install-global-git-hooks.sh --dry-run
+
+MODE="apply"
+if [[ "${1:-}" == "--dry-run" ]]; then
+  MODE="dry-run"
+fi
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
+SOURCE_DIR="$REPO_ROOT/scripts/codex-git-hooks"
+DEST_DIR="${ECC_GLOBAL_HOOKS_DIR:-$HOME/.codex/git-hooks}"
+STAMP="$(date +%Y%m%d-%H%M%S)"
+BACKUP_DIR="$HOME/.codex/backups/git-hooks-$STAMP"
+
+log() {
+  printf '[ecc-hooks] %s\n' "$*"
+}
+
+run_or_echo() {
+  if [[ "$MODE" == "dry-run" ]]; then
+    printf '[dry-run]'
+    printf ' %q' "$@"
+    printf '\n'
+  else
+    "$@"
+  fi
+}
+
+if [[ ! -d "$SOURCE_DIR" ]]; then
+  log "Missing source hooks directory: $SOURCE_DIR"
+  exit 1
+fi
+
+log "Mode: $MODE"
+log "Source hooks: $SOURCE_DIR"
+log "Global hooks destination: $DEST_DIR"
+
+if [[ -d "$DEST_DIR" ]]; then
+  log "Backing up existing hooks directory to $BACKUP_DIR"
+  run_or_echo mkdir -p "$BACKUP_DIR"
+  run_or_echo cp -R "$DEST_DIR" "$BACKUP_DIR/hooks"
+fi
+
+run_or_echo mkdir -p "$DEST_DIR"
+run_or_echo cp "$SOURCE_DIR/pre-commit" "$DEST_DIR/pre-commit"
+run_or_echo cp "$SOURCE_DIR/pre-push" "$DEST_DIR/pre-push"
+run_or_echo chmod +x "$DEST_DIR/pre-commit" "$DEST_DIR/pre-push"
+
+if [[ "$MODE" == "apply" ]]; then
+  prev_hooks_path="$(git config --global core.hooksPath || true)"
+  if [[ -n "$prev_hooks_path" ]]; then
+    log "Previous global hooksPath: $prev_hooks_path"
+  fi
+fi
+run_or_echo git config --global core.hooksPath "$DEST_DIR"
+
+log "Installed ECC global git hooks."
+log "Disable per repo by creating .ecc-hooks-disable in project root."
+log "Temporary bypass: ECC_SKIP_PRECOMMIT=1 or ECC_SKIP_PREPUSH=1"