fix: pre-landing review fixes

Review army findings (1 critical, auto-fixed with regression tests):

- CRITICAL (security specialist, verified live): redactFindingSpans spliced
  only the regex capture span, and pem.private_key / gcp.service_account
  capture just the BEGIN-header — the key body survived "redaction" and
  shipped via telemetry. Marker-only patterns now drop the whole payload
  (null, fail closed). Overlapping spans (Bearer+JWT on the same bytes) are
  coalesced before splicing so stale offsets can't leave partial secret
  bytes behind.
- gitStrict: drop the dead `|| r.status === null` disjunct (null !== 0
  already covers it); add the signal-kill/null-status regression test the
  docstring promised.
- security-dashboard human mode flags stale snapshots ("figures may be out
  of date") instead of presenting frozen counts as current.
- community-dashboard marker check uses jq when available — the grep-only
  variant misclassified whitespaced/reserialized bodies as legacy.
- telemetry fail-closed test now shadows bun with a failing stub
  (deterministic on any host layout); stale "five status cases" describe
  title renamed.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bin/gstack-security-dashboard

@@ -110,6 +110,10 @@ TOTAL="$(echo "$DATA" | jq -r '.security.attacks_last_7_days // 0' 2>/dev/null |
 echo "Attacks detected last 7 days: ${TOTAL}"
 if [ "$STATE" = "legacy" ]; then
   echo "  (unverified — legacy backend response; deploy the latest community-pulse for verified figures)"
+elif [ "$(echo "$DATA" | jq -r '.stale // false' 2>/dev/null)" = "true" ]; then
+  # The backend serves its last good snapshot when recompute fails — figures
+  # are real but frozen. Don't present them as current.
+  echo "  (stale snapshot — backend recompute failing; figures may be out of date)"
 elif [ "$TOTAL" = "0" ]; then
   echo "  (No attack attempts reported by the community yet. Good news.)"
 fi