fix(reset,stop): warn before a reset purges, skip and prune stale registries, refuse a guessed purge

reset.sh without --yes says the conversations are deleted for good before it
asks; without a terminal the refusal says so too. A registry that cannot be
created is skipped, since nothing can be registered there, and the directories
the fence created are removed on exit when still empty. stop --purge-conversation
refuses a conversation the row does not record instead of deleting the folder's
newest one.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VCgu9Fa9iT7TbJUSzdq4Ff

.agents/skills/multi-agent-mux-reset/scripts/reset.sh

@@ -36,7 +36,7 @@ while [ $# -gt 0 ]; do
 done
 
 if [ "$DRY_RUN" != "1" ] && [ "$YES" != "1" ] && [ ! -t 0 ]; then
-  echo "ERROR: not a terminal; run with -y/--yes (or --dry-run to inspect)" >&2
+  echo "ERROR: not a terminal, so the reset cannot ask; it permanently deletes conversations: run with -y/--yes once that is confirmed (or --dry-run to inspect)" >&2
   exit 3
 fi
 
@@ -115,11 +115,13 @@ case "$_acquire_rc" in
   *) _refuse_locked "cannot determine whether a review loop or another reset is running (ps unavailable?)" ;;
 esac
 FENCED=()
+CREATED=()
 _release_reset_lock() {
   local d
   for d in ${FENCED[@]+"${FENCED[@]}"}; do
     [ "$(_mam_lock_field "$d/.reset-in-progress" pid 2>/dev/null || true)" != "$$" ] || rm -f "$d/.reset-in-progress"
   done
+  [ "${#CREATED[@]}" -eq 0 ] || MAM_STATE_JSON="$STATE_JSON" "$PY" -m lib_py.reset prune-created --workspace "$WS" "${CREATED[@]}" || true
   mam_release_loop_lock "$RESET_MARKER" || true
   mam_release_loop_lock "$MARKER" || true
 }
@@ -154,6 +156,7 @@ fence_refusal=""
 while IFS= read -r line; do
   case "$line" in
     "fenced "*) FENCED+=("${line#fenced }") ;;
+    "created "*) CREATED+=("${line#created }") ;;
     "refused "*) fence_refusal="${line#refused }" ;;
   esac
 done <<< "$fence_out"
@@ -174,16 +177,19 @@ if [ "$pre_rc" -ne 0 ]; then
   exit 1
 fi
 
+_confirm_purge() {
+  local ans=""
+  echo "WARNING: this permanently deletes the conversations of the agents to reset above; they cannot be recovered."
+  read -r -p "$1 [y/N]: " ans || ans=""
+  case "$ans" in
+    y|Y|yes|Yes|YES) ;;
+    *) echo "Reset cancelled; nothing was changed"; exit 0 ;;
+  esac
+}
+
 if [ -f "$SPEC_FILE" ]; then
   MAM_STATE_JSON="$STATE_JSON" "$PY" -m lib_py.reset dry-run --workspace "$WS" || exit 1
-  if [ "$YES" != "1" ]; then
-    ans=""
-    read -r -p "Resume reset from $SPEC_FILE? [y/N]: " ans || ans=""
-    case "$ans" in
-      y|Y|yes|Yes|YES) ;;
-      *) echo "Reset cancelled; nothing was changed"; exit 0 ;;
-    esac
-  fi
+  [ "$YES" = "1" ] || _confirm_purge "Really resume the reset from $SPEC_FILE?"
 else
   PLAN_JSON="$(MAM_STATE_JSON="$STATE_JSON" "$PY" -m lib_py.reset plan --workspace "$WS")" || exit 1
   TARGET_COUNT="$(printf '%s' "$PLAN_JSON" | "$PY" -c 'import json,sys; print(len(json.load(sys.stdin).get("targets", [])))')"
@@ -192,14 +198,7 @@ else
     echo "nothing to reset"
     exit 0
   fi
-  if [ "$YES" != "1" ]; then
-    ans=""
-    read -r -p "Purge and recreate $TARGET_COUNT agents? [y/N]: " ans || ans=""
-    case "$ans" in
-      y|Y|yes|Yes|YES) ;;
-      *) echo "Reset cancelled; nothing was changed"; exit 0 ;;
-    esac
-  fi
+  [ "$YES" = "1" ] || _confirm_purge "Really purge and recreate $TARGET_COUNT agents?"
   printf '%s' "$PLAN_JSON" | "$PY" -m lib_py.reset write-spec --workspace "$WS" || exit 1
 fi