fix: a release its download client will not let Minstrel follow is held back, not taken every pass (#6176)

The Black Keys' Ohio Players was grabbed 40 times in a day. FabledExchange
already held the torrent under another category from before Minstrel took
the downloads over: the add answered "duplicate", which counted as added,
and Exchange's listing, filtered to Minstrel's category, never showed it.
Half an hour later the grab ended gone, and the next pass took it again.

- A duplicate add that the client does not list for Minstrel is not a
  grab: the release is held back for a day with the client's own reason
  (already downloading X (category)), and the search moves on. Forced,
  it is refused with that reason.
- A release that ends gone a second time within a week is held back for
  a day, whatever the cause.
- release_blocks gains the reason 'gone' (migration 0098), shown as
  "Held back: its download client lost track of it".

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/lifecycle/lifecycle_test.go

@@ -6,6 +6,7 @@ import (
 	"io"
 	"log/slog"
 	"os"
+	"strings"
 	"testing"
 	"time"
 
@@ -277,6 +278,52 @@ func TestLifecycle_ADownloadGoneFromTheClientEndsAfterHalfAnHour_Integration(t *
 	}
 }
 
+// A release that leaves its client a second time is held back, whatever the
+// cause (#6176): one release was taken 40 times in a day, each ending gone.
+func TestLifecycle_AReleaseGoneTwiceIsHeldBack_Integration(t *testing.T) {
+	st := newStack(t, downloader.Torrent{Name: "Daft Punk - RAM [FLAC]", Progress: 0.3, State: "downloading", NumSeeds: 4})
+	ctx := context.Background()
+	delete(st.client.held, hash)
+	st.client.held[other] = downloader.Torrent{Hash: other, Name: "Someone else's", Progress: 1, State: "uploading"}
+
+	st.s.Pass(ctx)
+	st.clock = st.clock.Add(31 * time.Minute)
+	if rep := st.s.Pass(ctx); rep.Gone != 1 {
+		t.Fatalf("first gone: %+v", rep)
+	}
+	if blocks, _ := st.q.ListReleaseBlocks(ctx); len(blocks) != 0 {
+		t.Fatalf("held back after one gone: %+v", blocks)
+	}
+
+	again, err := acquire.NewMemory(st.s.pool).Grabbed(ctx, dbq.InsertGrabParams{WantID: st.want.ID, InfoHash: hash,
+		Name: "Daft Punk - RAM [FLAC]", Key: hash, Client: "qbittorrent", SavePath: "/downloads", Origin: acquire.OriginSchedule},
+		pgtype.UUID{}, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// first_seen is the database's clock and the test's runs ahead of it, so
+	// the second grab may end on either pass; count both.
+	gone := st.s.Pass(ctx).Gone
+	st.clock = st.clock.Add(31 * time.Minute)
+	if gone += st.s.Pass(ctx).Gone; gone != 1 {
+		t.Fatalf("second grab ended gone %d times, want 1", gone)
+	}
+	blocks, err := st.q.ListReleaseBlocks(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(blocks) != 1 || blocks[0].Reason != acquire.BlockGone || !blocks[0].ExpiresAt.Valid {
+		t.Fatalf("blocks = %+v, want one timed gone block", blocks)
+	}
+	g, err := st.q.GetGrab(ctx, again.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if g.EndReason != EndGone || !strings.Contains(g.EndDetail, "held back until") {
+		t.Errorf("second grab %q: %s", g.EndReason, g.EndDetail)
+	}
+}
+
 func TestLifecycle_AnEmptyListIsNotAMeasurement_Integration(t *testing.T) {
 	st := newStack(t, downloader.Torrent{Name: "Daft Punk - RAM [FLAC]", Progress: 0.3, State: "downloading"})
 	ctx := context.Background()