App v0.2.27 and gateway 0.1.23

Skip Intro from Emby's own chapter markers, trickplay seek previews from
BIF files, a server-composed home hero ranked on Radarr/Sonarr dates and
review scores, and My Alerts as its own page behind the user picker.

Related titles now degrade at every step instead of returning empty, and
the "+" is back on Manage users so a second viewer can be added from the
launcher.

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

server/internal/recommend/engine_test.go

@@ -8,6 +8,7 @@ import (
 	"io"
 	"log/slog"
 	"net/url"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -875,3 +876,93 @@ func rowTitles(rows []Row) []string {
 	}
 	return out
 }
+
+func testSeeds(count int) []Seed {
+	seeds := make([]Seed, 0, count)
+	for index := 0; index < count; index++ {
+		id := "s" + strconv.Itoa(index)
+		seeds = append(seeds, Seed{ID: id, Name: "Title " + id})
+	}
+	return seeds
+}
+
+func seedIDs(seeds []Seed) []string {
+	out := make([]string, 0, len(seeds))
+	for _, seed := range seeds {
+		out = append(out, seed.ID)
+	}
+	return out
+}
+
+// The head of a household's history barely moves while they work through one series, so
+// the seeds must move without it.
+func TestSelectSeedsRotatesWithoutNewHistory(t *testing.T) {
+	seeds := testSeeds(12)
+	days := map[string]bool{}
+	for day := 1; day <= 14; day++ {
+		chosen := selectSeeds(seeds, 12, 3, "u1:2026-08-"+strconv.Itoa(day))
+		if len(chosen) != 3 {
+			t.Fatalf("day %d chose %d seeds", day, len(chosen))
+		}
+		days[strings.Join(seedIDs(chosen), ",")] = true
+	}
+	if len(days) < 4 {
+		t.Fatalf("a fortnight produced only %d distinct seed sets: %v", len(days), days)
+	}
+}
+
+// Rotation is within recency bands, never a shuffle of the whole window: the first row is
+// still anchored to something watched lately.
+func TestSelectSeedsKeepsRecencyBands(t *testing.T) {
+	seeds := testSeeds(12)
+	for day := 1; day <= 30; day++ {
+		chosen := selectSeeds(seeds, 12, 3, "u1:day-"+strconv.Itoa(day))
+		for index, seed := range chosen {
+			position, err := strconv.Atoi(strings.TrimPrefix(seed.ID, "s"))
+			if err != nil {
+				t.Fatalf("unexpected seed id %q", seed.ID)
+			}
+			if position < index*4 || position >= (index+1)*4 {
+				t.Fatalf("row %d drew %s from outside its band", index, seed.ID)
+			}
+		}
+	}
+}
+
+// Rows are rebuilt on every cache miss, so the same day must always yield the same seeds.
+func TestSelectSeedsIsStableWithinADay(t *testing.T) {
+	seeds := testSeeds(20)
+	first := seedIDs(selectSeeds(seeds, 12, 3, "u1:2026-08-07"))
+	for attempt := 0; attempt < 5; attempt++ {
+		if got := seedIDs(selectSeeds(seeds, 12, 3, "u1:2026-08-07")); !slices.Equal(got, first) {
+			t.Fatalf("same day produced %v then %v", first, got)
+		}
+	}
+	other := seedIDs(selectSeeds(seeds, 12, 3, "u2:2026-08-07"))
+	if slices.Equal(other, first) {
+		t.Log("two users may coincide; only a smoke check")
+	}
+}
+
+// A short history has nothing to rotate: take what there is, newest first.
+func TestSelectSeedsFallsBackToRecencyWhenShort(t *testing.T) {
+	if got := seedIDs(selectSeeds(testSeeds(2), 12, 3, "u1:day")); !slices.Equal(got, []string{"s0", "s1"}) {
+		t.Fatalf("short history = %v", got)
+	}
+	if got := selectSeeds(nil, 12, 3, "u1:day"); len(got) != 0 {
+		t.Fatalf("no history should seed nothing, got %v", got)
+	}
+}
+
+// A pool that does not divide evenly must not strand its oldest entries.
+func TestSelectSeedsLastBandTakesTheRemainder(t *testing.T) {
+	seeds := testSeeds(11)
+	reached := map[string]bool{}
+	for day := 1; day <= 40; day++ {
+		chosen := selectSeeds(seeds, 11, 3, "u1:day-"+strconv.Itoa(day))
+		reached[chosen[2].ID] = true
+	}
+	if !reached["s10"] {
+		t.Fatalf("the oldest seed was never reachable: %v", reached)
+	}
+}