fix: the details pane follows its secret's list when it reloads

A cached list is shown at once and reloaded in the background; the
selected secret's details stayed as first shown, old web page
included, until another secret was selected. When the reloaded list
has it changed, the details pane takes the new listing (a value shown
stays shown) and describes it afresh: its cached details came from
the old one.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

internal/ui/app/cache_test.go

@@ -2,6 +2,7 @@ package app
 
 import (
 	"context"
+	"slices"
 	"testing"
 	"time"
 
@@ -159,3 +160,33 @@ func TestMovingOnDropsUnsettledLoads(t *testing.T) {
 		t.Errorf("stopping on a subscription: %d calls, want 1", c.containers-before)
 	}
 }
+
+func TestReloadedListRefreshesShownSecret(t *testing.T) {
+	t.Parallel()
+	d, _, clock := newCachingDriver(t)
+	d.keys("3") // kv-app-prod's secrets, db-password selected
+	shown, _ := d.m.detail.Secret()
+	// What an older lazysecrets listed and cached for it.
+	const old = "https://portal.example/old"
+	key := d.m.selContainer
+	e := d.m.cache.objects[key]
+	items := slices.Clone(e.value)
+	for i := range items {
+		if items[i].ID == shown.ID {
+			items[i].URL = old
+		}
+	}
+	d.m.cache.objects[key] = entry[[]provider.Object]{items, e.at}
+	stale := shown
+	stale.URL = old
+	d.m.cache.details[detailKey(shown)] = entry[provider.Object]{stale, *clock}
+
+	// Away and back once the list is stale: it's shown from the cache,
+	// then reloaded, and the details pane follows.
+	d.keys("1", "j")
+	*clock = clock.Add(cacheTTL + time.Second)
+	d.keys("k", "3")
+	if got, _ := d.m.detail.Secret(); got.ID != shown.ID || got.URL == old {
+		t.Errorf("shown %s with %q after the reload", got.Name, got.URL)
+	}
+}