fix(ralph-wiggum): make stop hook's jq error handling reachable under set -e

[Yigtwxx]

Problem

plugins/ralph-wiggum/hooks/stop-hook.sh runs under set -euo pipefail and parses the last assistant transcript line with:

LAST_OUTPUT=$(echo "$LAST_LINE" | jq -r '...' 2>&1)

# Check if jq succeeded
if [[ $? -ne 0 ]]; then
  # friendly message, rm state file, exit 0

A plain VAR=$(cmd) assignment takes cmd's exit status, so if jq fails to parse (malformed/truncated transcript line), set -e aborts the script at the assignment — the $? check and the whole recovery branch below it are unreachable. Instead of the designed graceful stop (message to the user, .claude/ralph-loop.local.md cleaned up, exit 0), the hook dies with an unhandled nonzero exit and leaves the loop state file behind.

Fix

Guard the assignment so the failure is captured instead of fatal:

JQ_EXIT=0
LAST_OUTPUT=$(echo "$LAST_LINE" | jq -r '...' 2>&1) || JQ_EXIT=$?

if [[ $JQ_EXIT -ne 0 ]]; then

Behavior is otherwise identical: 2>&1 still captures jq's error text into LAST_OUTPUT for the diagnostic message.

Verification

• bash -n passes.
• Reproduced the pattern under set -euo pipefail: with the guard, a failing command substitution reaches the error branch with the right exit code; without it, the shell exits at the assignment.