fix(coach): delete-with-undo replaces the arm-forever confirm

The history rail + /coach/conversations armed a row on the first tap
and only disarmed on a successful delete — no timeout, no
outside-click reset — so a row armed minutes earlier deleted on a
later stray tap, and there was no way back once it fired. Replace it
with the same delayed-commit delete-with-undo the Documents surface
already uses: one tap hides the row and schedules the real DELETE a
few seconds out; the toast's Undo cancels it. Centralised in
useDeleteCoachConversationWithUndo so both surfaces, which carried
byte-identical arm/confirm logic, share one implementation.

messages/de.json

@@ -2262,7 +2262,7 @@
       "historySearchPlaceholder": "Unterhaltungen durchsuchen…",
       "historyEmpty": "Deine Unterhaltungen erscheinen hier. Stell eine Frage, um zu starten.",
       "historyDeleteAria": "Unterhaltung löschen",
-      "historyDeleteConfirm": "Diese Unterhaltung löschen? Das lässt sich nicht rückgängig machen.",
+      "historyDeleted": "Unterhaltung gelöscht",
       "sourcesTitle": "Worauf ich zugreife",
       "sourcesFresh": "Aktuell",
       "sourcesStale": "Veraltet",

messages/en.json

@@ -2262,7 +2262,7 @@
       "historySearchPlaceholder": "Search conversations…",
       "historyEmpty": "Your conversations will appear here. Ask anything to start.",
       "historyDeleteAria": "Delete conversation",
-      "historyDeleteConfirm": "Delete this conversation? This cannot be undone.",
+      "historyDeleted": "Conversation deleted",
       "sourcesTitle": "What I can see",
       "sourcesFresh": "Fresh",
       "sourcesStale": "Stale",

messages/es.json

@@ -2262,7 +2262,7 @@
       "historySearchPlaceholder": "Buscar en las conversaciones…",
       "historyEmpty": "Tus conversaciones aparecen aquí. Lanza una pregunta para empezar.",
       "historyDeleteAria": "Eliminar conversación",
-      "historyDeleteConfirm": "¿Eliminar esta conversación? No se puede deshacer.",
+      "historyDeleted": "Conversación eliminada",
       "sourcesTitle": "A qué accedo",
       "sourcesFresh": "Actuales",
       "sourcesStale": "Desactualizados",

messages/fr.json

@@ -2262,7 +2262,7 @@
       "historySearchPlaceholder": "Rechercher dans les conversations…",
       "historyEmpty": "Tes conversations s’affichent ici. Lance une question pour commencer.",
       "historyDeleteAria": "Supprimer la conversation",
-      "historyDeleteConfirm": "Supprimer cette conversation ? Action irréversible.",
+      "historyDeleted": "Conversation supprimée",
       "sourcesTitle": "Ce à quoi j’accède",
       "sourcesFresh": "À jour",
       "sourcesStale": "Obsolètes",

messages/it.json

@@ -2262,7 +2262,7 @@
       "historySearchPlaceholder": "Cerca nelle conversazioni…",
       "historyEmpty": "Le tue conversazioni compaiono qui. Fai una domanda per iniziare.",
       "historyDeleteAria": "Elimina conversazione",
-      "historyDeleteConfirm": "Eliminare questa conversazione? Non si può annullare.",
+      "historyDeleted": "Conversazione eliminata",
       "sourcesTitle": "A cosa accedo",
       "sourcesFresh": "Aggiornate",
       "sourcesStale": "Datate",

messages/pl.json

@@ -2262,7 +2262,7 @@
       "historySearchPlaceholder": "Szukaj w rozmowach…",
       "historyEmpty": "Twoje rozmowy pojawią się tutaj. Zadaj pytanie, aby zacząć.",
       "historyDeleteAria": "Usuń rozmowę",
-      "historyDeleteConfirm": "Usunąć tę rozmowę? Tego nie da się cofnąć.",
+      "historyDeleted": "Rozmowa usunięta",
       "sourcesTitle": "Do czego mam dostęp",
       "sourcesFresh": "Aktualne",
       "sourcesStale": "Nieaktualne",

src/app/coach/conversations/page.tsx

@@ -10,6 +10,7 @@ import {
   Target,
   Trash2,
 } from "lucide-react";
+import { toast } from "sonner";
 
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -18,7 +19,7 @@ import { QueryErrorCard } from "@/components/ui/query-error-card";
 import { COACH_SCROLLBAR } from "@/components/insights/coach-panel/message-thread";
 import {
   useCoachConversations,
-  useDeleteCoachConversation,
+  useDeleteCoachConversationWithUndo,
 } from "@/components/insights/coach-panel/use-coach";
 import type { CoachConversationDTO } from "@/lib/ai/coach/types";
 import { useCoachLaunch } from "@/lib/insights/coach-launch-context";
@@ -102,16 +103,17 @@ function CoachConversationsBody() {
   const router = useRouter();
   const { conversations, isLoading, isError, refetch } =
     useCoachConversations();
-  const deleteMutation = useDeleteCoachConversation();
+  const { pendingDeleteIds, requestDelete, undoDelete } =
+    useDeleteCoachConversationWithUndo();
   const [filter, setFilter] = useState<string>("");
-  const [confirmId, setConfirmId] = useState<string | null>(null);
 
   // Mirror the rail's title substring filter.
   const filtered = useMemo(() => {
     const q = filter.trim().toLowerCase();
-    if (!q) return conversations;
-    return conversations.filter((c) => c.title.toLowerCase().includes(q));
-  }, [conversations, filter]);
+    const visible = conversations.filter((c) => !pendingDeleteIds.has(c.id));
+    if (!q) return visible;
+    return visible.filter((c) => c.title.toLowerCase().includes(q));
+  }, [conversations, filter, pendingDeleteIds]);
 
   const groups = useMemo(() => groupByRecency(filtered), [filtered]);
 
@@ -120,13 +122,17 @@ function CoachConversationsBody() {
     router.push(`/coach?c=${id}`);
   }
 
+  // v1.30.1 M5 — one tap deletes (with an Undo toast); see
+  // `use-coach.ts`'s `useDeleteCoachConversationWithUndo` for the
+  // rationale — this mirrors the rail's identical fix.
   function handleDeleteRequest(id: string) {
-    if (confirmId === id) {
-      deleteMutation.mutate(id);
-      setConfirmId(null);
-    } else {
-      setConfirmId(id);
-    }
+    requestDelete(id);
+    toast.success(t("insights.coach.historyDeleted"), {
+      action: {
+        label: t("common.undo"),
+        onClick: () => undoDelete(id),
+      },
+    });
   }
 
   return (
@@ -212,7 +218,6 @@ function CoachConversationsBody() {
               </h2>
               <ul className="flex flex-col gap-1">
                 {group.conversations.map((c) => {
-                  const isConfirming = confirmId === c.id;
                   return (
                     <li
                       key={c.id}
@@ -260,18 +265,9 @@ function CoachConversationsBody() {
                         variant="ghost"
                         size="icon-lg"
                         onClick={() => handleDeleteRequest(c.id)}
-                        aria-label={
-                          isConfirming
-                            ? t("insights.coach.historyDeleteConfirm")
-                            : t("insights.coach.historyDeleteAria")
-                        }
+                        aria-label={t("insights.coach.historyDeleteAria")}
                         data-slot="coach-conversations-delete"
-                        data-confirming={isConfirming ? "true" : undefined}
-                        className={cn(
-                          "shrink-0",
-                          isConfirming &&
-                            "text-destructive hover:text-destructive",
-                        )}
+                        className="shrink-0"
                       >
                         <Trash2 className="size-4" aria-hidden="true" />
                       </Button>

src/components/insights/coach-panel/history-rail.tsx

@@ -2,6 +2,7 @@
 
 import { useMemo, useState } from "react";
 import { MessagesSquare, Paperclip, Search, Trash2 } from "lucide-react";
+import { toast } from "sonner";
 
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
@@ -10,7 +11,10 @@ import { useTranslations } from "@/lib/i18n/context";
 import { formatRelativeTime } from "@/lib/i18n/relative-time";
 
 import { COACH_SCROLLBAR } from "./message-thread";
-import { useCoachConversations, useDeleteCoachConversation } from "./use-coach";
+import {
+  useCoachConversations,
+  useDeleteCoachConversationWithUndo,
+} from "./use-coach";
 
 /**
  * v1.4.20 phase B2b — conversation history rail.
@@ -52,26 +56,31 @@ export function HistoryRail({
 }: HistoryRailProps) {
   const { t } = useTranslations();
   const { conversations, isLoading } = useCoachConversations();
-  const deleteMutation = useDeleteCoachConversation();
+  const { pendingDeleteIds, requestDelete, undoDelete } =
+    useDeleteCoachConversationWithUndo();
   const [filter, setFilter] = useState<string>("");
-  const [confirmId, setConfirmId] = useState<string | null>(null);
 
   const filtered = useMemo(() => {
     const q = filter.trim().toLowerCase();
-    if (!q) return conversations;
-    return conversations.filter((c) => c.title.toLowerCase().includes(q));
-  }, [conversations, filter]);
+    const visible = conversations.filter((c) => !pendingDeleteIds.has(c.id));
+    if (!q) return visible;
+    return visible.filter((c) => c.title.toLowerCase().includes(q));
+  }, [conversations, filter, pendingDeleteIds]);
 
+  // v1.30.1 M5 — a single tap hides the row and schedules the real
+  // delete; the toast's Undo action cancels it within the grace
+  // window. Replaces the old arm-then-tap-again confirm, which never
+  // disarmed. If the user just deleted the active thread, the drawer
+  // is listening to `onSelect` for navigation; we leave it to the
+  // parent to clear `activeId` when the conversation disappears.
   function handleDeleteRequest(id: string) {
-    if (confirmId === id) {
-      deleteMutation.mutate(id);
-      setConfirmId(null);
-      // If the user just deleted the active thread, the drawer is
-      // listening to `onSelect` for navigation; we leave it to the
-      // parent to clear `activeId` when the conversation disappears.
-    } else {
-      setConfirmId(id);
-    }
+    requestDelete(id);
+    toast.success(t("insights.coach.historyDeleted"), {
+      action: {
+        label: t("common.undo"),
+        onClick: () => undoDelete(id),
+      },
+    });
   }
 
   return (
@@ -141,7 +150,6 @@ export function HistoryRail({
         ) : (
           filtered.map((c) => {
             const isActive = c.id === activeId;
-            const isConfirming = confirmId === c.id;
             return (
               <div
                 key={c.id}
@@ -187,26 +195,18 @@ export function HistoryRail({
                 </button>
                 {/* v1.4.27 R3d MB2 — drop the hover-only `opacity-0`
                     reveal: touch surfaces have no hover, so the delete
-                    affordance was invisible on mobile. The button now
+                    affordance was invisible on mobile. The button
                     sits at 44 px always-visible per the WCAG 2.5.5
-                    floor; confirming state stays styled via the
-                    `data-confirming` attribute. */}
+                    floor. v1.30.1 M5 — one tap deletes (with an Undo
+                    toast); the old arm/confirm double-tap is gone. */}
                 <Button
                   type="button"
                   variant="ghost"
                   size="icon"
                   onClick={() => handleDeleteRequest(c.id)}
-                  aria-label={
-                    isConfirming
-                      ? t("insights.coach.historyDeleteConfirm")
-                      : t("insights.coach.historyDeleteAria")
-                  }
+                  aria-label={t("insights.coach.historyDeleteAria")}
                   data-slot="coach-history-delete"
-                  data-confirming={isConfirming ? "true" : undefined}
-                  className={cn(
-                    "size-11 shrink-0",
-                    isConfirming && "text-destructive hover:text-destructive",
-                  )}
+                  className="size-11 shrink-0"
                 >
                   <Trash2 className="size-4" aria-hidden="true" />
                 </Button>

src/components/insights/coach-panel/use-coach.ts

@@ -128,6 +128,87 @@ export function useDeleteCoachConversation() {
   });
 }
 
+// v1.30.1 M5 — delayed-commit delete window, in milliseconds. Long
+// enough to read + tap Undo, short enough that the eventual DELETE
+// isn't a surprise days later.
+const CONVERSATION_DELETE_UNDO_MS = 6000;
+
+/**
+ * v1.30.1 M5 — replaces the old "tap once to arm, tap the same row
+ * again to delete" confirm, which never disarmed (a row armed minutes
+ * earlier deleted on a later stray tap) and had no way back once fired.
+ * Mirrors the Documents delete-with-undo pattern instead: a single tap
+ * hides the row immediately and schedules the real
+ * `DELETE /api/insights/chat/[id]` after `CONVERSATION_DELETE_UNDO_MS`;
+ * calling `undoDelete` within that window cancels the network call and
+ * un-hides the row. `pendingDeleteIds` is a client-only hide filter —
+ * consumers subtract it from whatever list they render.
+ *
+ * Centralised here (rather than duplicated in the rail + the standalone
+ * `/coach/conversations` page, which previously carried byte-identical
+ * arm/confirm logic) so both surfaces share one implementation.
+ */
+export function useDeleteCoachConversationWithUndo() {
+  const deleteMutation = useDeleteCoachConversation();
+  const [pendingDeleteIds, setPendingDeleteIds] = useState<Set<string>>(
+    () => new Set(),
+  );
+  const timers = useRef(new Map<string, ReturnType<typeof setTimeout>>());
+
+  useEffect(() => {
+    // A closed drawer / unmounted page must not silently lose a
+    // scheduled delete: fire any still-pending ones immediately rather
+    // than leaking the timer (or worse, never deleting at all).
+    const timerMap = timers.current;
+    return () => {
+      for (const [id, timer] of timerMap) {
+        clearTimeout(timer);
+        deleteMutation.mutate(id);
+      }
+      timerMap.clear();
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps -- run once on unmount only
+  }, []);
+
+  const requestDelete = useCallback(
+    (id: string) => {
+      setPendingDeleteIds((prev) => {
+        const next = new Set(prev);
+        next.add(id);
+        return next;
+      });
+      const timer = setTimeout(() => {
+        timers.current.delete(id);
+        setPendingDeleteIds((prev) => {
+          if (!prev.has(id)) return prev;
+          const next = new Set(prev);
+          next.delete(id);
+          return next;
+        });
+        deleteMutation.mutate(id);
+      }, CONVERSATION_DELETE_UNDO_MS);
+      timers.current.set(id, timer);
+    },
+    [deleteMutation],
+  );
+
+  const undoDelete = useCallback((id: string) => {
+    const timer = timers.current.get(id);
+    if (timer) {
+      clearTimeout(timer);
+      timers.current.delete(id);
+    }
+    setPendingDeleteIds((prev) => {
+      if (!prev.has(id)) return prev;
+      const next = new Set(prev);
+      next.delete(id);
+      return next;
+    });
+  }, []);
+
+  return { pendingDeleteIds, requestDelete, undoDelete };
+}
+
 /**
  * v1.29.x (S7) — attach a stored document to an EXISTING fenced (or about-to-be-
  * fenced) conversation. On success invalidates the conversation detail + rail so