Show the recent strip only where it is not a duplicate

The strip is the head of the same updated_at DESC reading list the All tab
renders, and app.html put it on every tab: on a small library it repeated the
list immediately below it while eating ~230px of the first phone screen, and on
Archived and Finished it showed reading series above the opposite bucket.

buildListView now fills Recent only for tab=all with more reading series than
the strip holds. Because the strip lives outside the htmx-swapped #list, an
in-page tab switch cannot re-render it, so applyFilter also decides its
visibility from the active tab; setActiveTab pokes it after a swap.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

backend/web_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"fmt"
 	"net/http"
 	"net/http/httptest"
 	"net/url"
@@ -578,25 +579,58 @@ func TestTabsShowOnlyTheirBucket(t *testing.T) {
 	}
 }
 
-func TestRecentStripExcludesArchivedAndFinished(t *testing.T) {
+// stripOf returns everything above the list, which is where the recent section
+// renders.
+func stripOf(t *testing.T, srv http.Handler, cfg Config, tab string) string {
+	t.Helper()
+	req := httptest.NewRequest(http.MethodGet, "/?tab="+tab, nil)
+	req.AddCookie(sessionCookie(t, cfg))
+	rr := httptest.NewRecorder()
+	srv.ServeHTTP(rr, req)
+	body := rr.Body.String()
+	if i := strings.Index(body, `id="list"`); i >= 0 {
+		body = body[:i]
+	}
+	return body
+}
+
+// The strip is the head of the same list the All tab renders, so it only shows
+// where it is not a pure duplicate: on All, with more reading series than it
+// holds.
+func TestRecentStripOnlyOnAllAndOnlyWhenItAddsSomething(t *testing.T) {
 	cfg := webConfig()
 	srv, store := newWebTestServer(t, cfg)
 	seedStatusRows(t, store)
 
-	req := httptest.NewRequest(http.MethodGet, "/?tab=archived", nil)
-	req.AddCookie(sessionCookie(t, cfg))
-	rr := httptest.NewRecorder()
-	srv.ServeHTTP(rr, req)
+	for _, tab := range []string{"all", "new", "fav", "archived", "finished"} {
+		if strings.Contains(stripOf(t, srv, cfg, tab), `class="recent"`) {
+			t.Fatalf("tab %s rendered the strip for a library of one reading series", tab)
+		}
+	}
 
-	strip := rr.Body.String()
-	if i := strings.Index(strip, `id="list"`); i >= 0 {
-		strip = strip[:i] // everything above the list is the recent section
+	// Past recentCount the strip stops repeating the whole list.
+	for i := 0; i <= recentCount; i++ {
+		b := Bookmark{
+			Key: fmt.Sprintf("asura:more%d", i), Site: "asura",
+			SeriesID: fmt.Sprintf("more%d", i), Title: fmt.Sprintf("MoreReading%d", i),
+			Status: statusReading, LastChapterNum: 1, UpdatedAt: time.Now().UnixMilli(),
+		}
+		if _, err := store.Upsert(b); err != nil {
+			t.Fatalf("seed %s: %v", b.Key, err)
+		}
+	}
+
+	strip := stripOf(t, srv, cfg, "all")
+	if !strings.Contains(strip, `class="recent"`) {
+		t.Fatal("strip missing on All with more reading series than it shows")
 	}
 	if strings.Contains(strip, "ArchivedOne") || strings.Contains(strip, "FinishedOne") {
 		t.Fatal("recent strip included an archived or finished series")
 	}
-	if !strings.Contains(strip, "ReadingOne") {
-		t.Fatal("recent strip dropped the reading series")
+	for _, tab := range []string{"new", "fav", "archived", "finished"} {
+		if strings.Contains(stripOf(t, srv, cfg, tab), `class="recent"`) {
+			t.Fatalf("tab %s rendered the strip", tab)
+		}
 	}
 }