feat(c7): incident response — severity classifier + scoped kill-switch + runbook (V23)

Closes the last fully-[planned] Track-C dimension (was scored 1).
- incident.sh raise <event>: classify severity via incident-severity.map
  (LOW/MED/HIGH/CRIT), record a structured entry (owner routing), and for
  HIGH/CRIT auto-engage the scoped kill-switch + dispatch an alert (reuses H6
  alert-dispatch.sh). Exit 2 on HIGH/CRIT so a pipeline gate goes red.
- kill-switch.sh engage/clear/check/status, scoped by project/model/provider
  (+ global). `check` exits 2 when engaged so gates honor it.
- casan-harness.sh honors an engaged kill-switch before running (opt-in
  CASAN_KILLSWITCH_ENFORCE=1, default OFF → baseline unchanged).
- incident-runbook.md: severity→owner→response + postmortem template + prod TODO.
- phase-c7-incident-tests.sh: 15 checks — severity grading, auto kill-switch on
  HIGH/CRIT, MED-only records, lifecycle, global scope, structured record, and
  the production wrapper refusing to run under an engaged switch.

Baselines: run-casan4 35/35, adversarial 44/44. New suite total: 175 → 190.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

AINative_OKR_CASAN5/.specify/scripts/bash/casan-harness.sh

@@ -82,6 +82,20 @@ APPROVED_INPUT="$TMP_DIR/governance-approved-$TRACE_SUFFIX.txt"
 RAW_OUTPUT="$TMP_DIR/raw-output-$TRACE_SUFFIX.txt"
 
 casan_log debug harness "action=$ACTION_NAME input=$INPUT_FILE output=$FINAL_OUTPUT key=${IDEMPOTENCY_KEY:0:12}…"
+
+# C7: honor an engaged kill-switch before doing any work (incident containment).
+# Opt-in (default off) so the baseline is unchanged; production sets it on.
+if [[ "${CASAN_KILLSWITCH_ENFORCE:-0}" == "1" ]]; then
+  KS_SCOPE="${CASAN_KILLSWITCH_SCOPE:-project}"
+  KS_ID="${CASAN_KILLSWITCH_ID:-${CASAN_PROJECT:-current}}"
+  if ! bash "$SCRIPT_DIR/kill-switch.sh" check "$KS_SCOPE" "$KS_ID" >/dev/null 2>&1; then
+    casan_log error harness "KILL_SWITCH_ACTIVE scope=$KS_SCOPE id=$KS_ID — refusing to run $ACTION_NAME"
+    : > "$FINAL_OUTPUT"
+    echo "KILL_SWITCH_ACTIVE scope=$KS_SCOPE id=$KS_ID action=$ACTION_NAME" >&2
+    exit 2
+  fi
+fi
+
 run_phase "H4-in" "$SCRIPT_DIR/security-check.sh" "$INPUT_FILE" "$SAFE_INPUT" input
 run_phase "H5" "$SCRIPT_DIR/governance-check.sh" "$SAFE_INPUT" "$APPROVED_INPUT" "$ACTION_NAME"