spec-spine: Hook for Claude Code

{
  "PreToolUse": [
    {
      "matcher": "Bash",
      "hooks": [
        {
          "type": "command",
          "command": "command -v jq >/dev/null 2>&1 || { echo '[hook] jq missing, push gate and PR gate skipped'; exit 0; }\npayload=$(cat)\ncmd=$(printf '%s' \"$payload\" | jq -r '.tool_input.command // empty' 2>/dev/null)\nhookcwd=$(printf '%s' \"$payload\" | jq -r '.cwd // empty' 2>/dev/null)\n# The repo the command acts on, NOT the session's project: a multi-repo session\n# pushes and opens PRs in whichever tree the command names. Honour an explicit\n# `cd <dir>` prefix, else the hook's own cwd, then ask git for the toplevel.\ntarget=$(printf '%s' \"$cmd\" | sed -n 's/^[[:space:]]*cd[[:space:]]\\{1,\\}\\([^&;|]*\\).*/\\1/p' | head -1 | sed 's/[[:space:]]*$//')\ntarget=$(printf '%s' \"$target\" | sed \"s|^~|$HOME|\")\n[ -n \"$target\" ] || target=\"$hookcwd\"\n[ -n \"$target\" ] || target=.\nroot=$(git -C \"$target\" rev-parse --show-toplevel 2>/dev/null) || root=\"$target\"\n\n# Spec 093 3.1: the protected branch is RESOLVED for the repository the command\n# acts on, never assumed to be `main`. Highest wins: $SPEC_SPINE_DEFAULT_BRANCH,\n# then the remote's own HEAD (a clone sets it, so most adopters need no\n# configuration at all), then `main` as a compatibility floor. Each step falls\n# back rather than refusing, and step 3 always answers, so the gate reaches a\n# verdict for every repository. Resolution asks git and never the spec-spine\n# binary: the push half of this hook runs on git alone, which is why it still\n# protects a repository where the binary is absent or /setup has not been run.\ndefault_branch() {\n  if [ -n \"${SPEC_SPINE_DEFAULT_BRANCH:-}\" ]; then echo \"${SPEC_SPINE_DEFAULT_BRANCH}\"; return 0; fi\n  h=$(git -C \"$1\" symbolic-ref --short refs/remotes/origin/HEAD 2>/dev/null) && [ -n \"$h\" ] && { echo \"${h#origin/}\"; return 0; }\n  echo main\n}\n\n# Anchored on the command that actually invokes the push verb (spec 093\n# 3.1). The o