feat(coach): add an opt-out for proactive ambient suggestions

Add a per-user toggle that turns off the proactive ambient example suggestions
(the daily seeded opener on the Coach hero). The flag rides the existing coach
notification-prefs blob (coach.ambientSuggestions, default on) — no schema
change — and a shared hook makes it the single source every ambient suggestion
surface consults, so the seeded opener and its fetch both stand down when off.

src/components/settings/coach-nudge-card.tsx

@@ -33,6 +33,7 @@ interface CoachPrefsShape {
   nudgeVitals: boolean;
   nudgeRoutine: boolean;
   nudgeFrequency: "weekly" | "biweekly";
+  ambientSuggestions: boolean;
 }
 
 interface NotificationPrefsShape {
@@ -45,6 +46,7 @@ const COACH_PREF_DEFAULTS: CoachPrefsShape = {
   nudgeVitals: true,
   nudgeRoutine: true,
   nudgeFrequency: "weekly",
+  ambientSuggestions: true,
 };
 
 const GROUP_FIELDS = [
@@ -254,6 +256,28 @@ export function CoachNudgeCard({
           </div>
         </div>
       )}
+      {/* v1.25.0 — proactive ambient SUGGESTIONS opt-out. Independent of the
+          push-nudge master switch above (a user can keep nudges but silence
+          the example prompts), so it sits outside the `enabled` gate and rides
+          the same `coach` prefs blob. */}
+      <div className="border-border/60 mt-4 flex min-h-11 items-center justify-between gap-3 border-t pt-4">
+        <div className="min-w-0">
+          <p className="text-sm">
+            {t("notifications.coachNudge.suggestionsLabel")}
+          </p>
+          <p className="text-muted-foreground text-xs">
+            {t("notifications.coachNudge.suggestionsDesc")}
+          </p>
+        </div>
+        <Switch
+          checked={resolved.ambientSuggestions}
+          onCheckedChange={(next) =>
+            patchCoach({ ambientSuggestions: next }, null)
+          }
+          disabled={!isAuthenticated || saving}
+          aria-label={t("notifications.coachNudge.suggestionsAria")}
+        />
+      </div>
       {msg && (
         <p
           role="status"