fix(plan-tune): shared accumulation JS as a quoted string, not a heredoc (heredoc pipe-deadlock guard)

Co-authored-by: capy-ai[bot] <230910855+capy-ai[bot]@users.noreply.github.com>

bin/gstack-developer-profile

@@ -414,7 +414,7 @@ do_gap() {
 # and about eight sessions pinned it at 1.0 (#2623). A row without a
 # session_id is its own session.
 # -----------------------------------------------------------------------
-ACCUMULATE_SIGNALS_JS=$(cat <<'JS'
+ACCUMULATE_SIGNALS_JS='
 function accumulateSignals(lines, QUESTIONS, SIGNAL_MAP, dims) {
   let cap = 0;
   for (const byChoice of Object.values(SIGNAL_MAP)) {
@@ -442,7 +442,7 @@ function accumulateSignals(lines, QUESTIONS, SIGNAL_MAP, dims) {
     const deltas = (def && def.signal_key && SIGNAL_MAP[def.signal_key]?.[e.user_choice]) || [];
     if (deltas.length === 0) continue;
     signalEvents++;
-    const session = typeof e.session_id === 'string' && e.session_id ? e.session_id : 'row-' + count;
+    const session = typeof e.session_id === "string" && e.session_id ? e.session_id : "row-" + count;
     const sums = sessions.get(session) || {};
     sessions.set(session, sums);
     for (const d of deltas) {
@@ -462,8 +462,7 @@ function accumulateSignals(lines, QUESTIONS, SIGNAL_MAP, dims) {
   }
   return { cap, totals, contributing, rows, capped, count, signalEvents, skills, qids, days };
 }
-JS
-)
+'
 
 # -----------------------------------------------------------------------
 # Derive: recompute inferred dimensions from question-events.jsonl