fix(coach): default to new chat and never dead-end on conversations

Reverse the resume-most-recent entry default: opening the Coach now lands
on the new-chat hero. The only exception is an unread coach-initiated
message (nudge-status `unread`), which auto-opens the most-recent thread so
the user sees what the Coach wrote. The `?c=<id>` deep-link is unchanged.

Add a dedicated, always-visible Conversations button (plus a New chat
button) to the page surface so reaching past conversations no longer hides
in the composer menu. The drawer's Conversations handoff now routes to
`/coach?view=conversations`, which opens the history drawer on arrival, so
the side-view to full-view path always shows the list instead of a blank
pane.

src/components/insights/coach-panel/__tests__/coach-conversation-deeplink.test.tsx

@@ -135,4 +135,25 @@ describe("<CoachConversation> page deep-link (#67)", () => {
     // though recent conversations exist in the cache.
     expect(html).toContain('data-slot="coach-hero"');
   });
+
+  // v1.19.1 (C2) — a dedicated, always-visible Conversations button on the
+  // page surface (not buried in the composer `+` menu).
+  it("renders the dedicated Conversations button on the page surface", () => {
+    const html = render(<CoachConversation surface="page" />, makeClient());
+    expect(html).toContain('data-slot="coach-page-conversations"');
+    expect(html).toContain('data-slot="coach-page-new-chat"');
+  });
+
+  // v1.19.1 (C5) — entering via the drawer handoff (`?view=conversations`)
+  // keeps the new-chat hero (no thread auto-resumed) while opening the
+  // history drawer; the toolbar + button stay present so the pane is never
+  // a blank dead-end.
+  it("keeps the hero and toolbar when opened with openHistoryOnMount", () => {
+    const html = render(
+      <CoachConversation surface="page" openHistoryOnMount />,
+      makeClient(),
+    );
+    expect(html).toContain('data-slot="coach-hero"');
+    expect(html).toContain('data-slot="coach-page-conversations"');
+  });
 });

src/components/insights/coach-panel/coach-conversation.tsx

@@ -3,7 +3,7 @@
 import { useEffect, useReducer, useState } from "react";
 import Link from "next/link";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
-import { Plus, Settings, Sparkles } from "lucide-react";
+import { MessagesSquare, Plus, Settings, Sparkles } from "lucide-react";
 import { toast } from "sonner";
 
 import { Button } from "@/components/ui/button";
@@ -137,6 +137,13 @@ export interface CoachConversationProps {
    * "new chat" or thread switch is never overridden.
    */
   autoOpenMostRecent?: boolean;
+  /**
+   * v1.19.1 (C5) — page surface only: open the conversation-history drawer
+   * once on mount. The drawer's "Conversations" handoff routes to
+   * `/coach?view=conversations`, which sets this so the user always sees the
+   * conversation list on arrival instead of a blank new-chat pane.
+   */
+  openHistoryOnMount?: boolean;
 }
 
 export function CoachConversation({
@@ -152,6 +159,7 @@ export function CoachConversation({
   surface,
   initialConversationId,
   autoOpenMostRecent = false,
+  openHistoryOnMount = false,
 }: CoachConversationProps) {
   const { t } = useTranslations();
 
@@ -165,7 +173,12 @@ export function CoachConversation({
   // the composer's `+` actions menu. Replaces the old inline collapsible
   // rail + top rail-tray strip; the top header bar is gone entirely on the
   // page so the composer is the single control hub.
-  const [historyDrawerOpen, setHistoryDrawerOpen] = useState(false);
+  // v1.19.1 (C5) — seed the history drawer open when the page is entered via
+  // the drawer's "Conversations" handoff (`?view=conversations`), so the
+  // list is on screen immediately rather than a blank hero.
+  const [historyDrawerOpen, setHistoryDrawerOpen] = useState(
+    () => openHistoryOnMount,
+  );
   const [inputValue, setInputValue] = useResettableValue(prefill ?? "");
   // v1.16.4 — self-context backflow: `pendingAdopt` raises a quiet
   // offer to fold a clarifying-question answer back into the
@@ -484,6 +497,37 @@ export function CoachConversation({
         data-variant={surface}
         className={cn("flex min-h-0 flex-1 flex-col", className)}
       >
+        {/* v1.19.1 (C2) — a clear, always-visible "Conversations" button on
+            the page surface. The composer's `+` menu still carries the same
+            action, but the maintainer wanted an obvious, dedicated affordance
+            to reach past conversations rather than one buried in a menu. */}
+        <div
+          data-slot="coach-page-toolbar"
+          className="flex shrink-0 items-center justify-between gap-2 px-4 pt-2 sm:px-6"
+        >
+          <Button
+            type="button"
+            variant="ghost"
+            size="sm"
+            onClick={() => setHistoryDrawerOpen(true)}
+            data-slot="coach-page-conversations"
+            className="text-muted-foreground hover:text-foreground -ml-1 gap-1.5"
+          >
+            <MessagesSquare className="size-4" aria-hidden="true" />
+            {t("insights.coach.historyTitle")}
+          </Button>
+          <Button
+            type="button"
+            variant="ghost"
+            size="sm"
+            onClick={handleNewChat}
+            data-slot="coach-page-new-chat"
+            className="text-muted-foreground hover:text-foreground -mr-1 gap-1.5"
+          >
+            <Plus className="size-4" aria-hidden="true" />
+            {t("insights.coach.newChat")}
+          </Button>
+        </div>
         {heroActive ? (
           <CoachHero composer={composerNode} />
         ) : (

src/components/insights/coach-panel/coach-drawer.tsx

@@ -88,6 +88,17 @@ export function CoachDrawer({ open, onOpenChange, prefill }: CoachDrawerProps) {
     router.push("/coach");
   }, [onOpenChange, router]);
 
+  // v1.19.1 (C5) — the drawer's "Conversations" affordance hands off to the
+  // full page WITH the `?view=conversations` flag so the page opens the
+  // conversation-history drawer on arrival. Previously it shared
+  // `handleMaximize` and, after the v1.19.1 new-chat default (C1), landed on
+  // a blank hero with no list — the dead-end the maintainer reported.
+  const handleOpenConversations = useCallback(() => {
+    onOpenChange(false);
+    resetRef.current?.();
+    router.push("/coach?view=conversations");
+  }, [onOpenChange, router]);
+
   return (
     <Sheet open={open} onOpenChange={handleOpenChange}>
       <SheetContent
@@ -118,9 +129,10 @@ export function CoachDrawer({ open, onOpenChange, prefill }: CoachDrawerProps) {
           autoFocusComposer
           registerReset={registerReset}
           // v1.16.1 — the "Conversations" affordance hands off to the
-          // full-page route (same path as maximize) instead of opening
-          // the broken in-panel left tray.
-          onRequestFullView={handleMaximize}
+          // full-page route instead of opening the broken in-panel left
+          // tray. v1.19.1 (C5) — it now carries `?view=conversations` so the
+          // page opens the history list on arrival, never a blank hero.
+          onRequestFullView={handleOpenConversations}
           // Radix requires an accessible name + description on the
           // dialog content. Mount them through the title/description
           // render-props so the page can swap in a plain heading.