fix(server): apply skip rule on auto-close instead of force-hiding orphans

autoClosePriorOpen hardcoded was_skipped=true for every orphaned
play_event (a play_started whose play_ended never arrived, e.g. the
client backgrounded mid-track). That hid fully-listened tracks from
History — a play that sat open past its own length was capped to the
track duration (ratio ~1) yet still flagged skipped. Observed live:
History showed 3 plays for a day of listening because most rows were
auto-closed orphans marked skipped.

Now the auto-close applies the same skip rule as RecordPlayEnded to the
duration-capped elapsed estimate: ratio >= threshold OR elapsed >= the
duration floor -> a real play that lands in History; a genuine
quick-abandon still classifies as a skip. Still writes no skip_events
row, so the ambiguous auto-close never feeds the skip-ratio /
recommendation signal.

This is the server half. The client-side root cause (backgrounded
track transitions never closed, orphaning the rows in the first place)
is tracked separately.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

internal/playevents/writer_test.go

@@ -122,14 +122,32 @@ func TestRecordPlayStarted_AutoClosesPriorOpenRow(t *testing.T) {
 	if !prior.EndedAt.Valid {
 		t.Errorf("prior should be closed")
 	}
-	if !prior.WasSkipped {
-		t.Errorf("prior should be marked was_skipped=true (auto-close convention)")
+	// 45s elapsed on a 200s track clears the 30s duration threshold, so the
+	// skip rule's AND fails -> NOT a skip. An orphan that played long enough
+	// to count must still land in history rather than being force-hidden.
+	if prior.WasSkipped {
+		t.Errorf("auto-close at 45s should apply the skip rule -> was_skipped=false")
 	}
 	if prior.DurationPlayedMs == nil || *prior.DurationPlayedMs != 45_000 {
 		t.Errorf("duration_played_ms = %v, want 45000", prior.DurationPlayedMs)
 	}
 }
 
+func TestRecordPlayStarted_AutoCloseShortPlayIsSkip(t *testing.T) {
+	f := newFixture(t, 200_000)
+	t1 := time.Now().UTC()
+	first, _ := f.w.RecordPlayStarted(context.Background(), f.user, f.track, "c", t1)
+	// 5s elapsed: ratio 0.025 < 0.5 AND 5000 < 30000 -> both fail -> a skip.
+	t2 := t1.Add(5 * time.Second)
+	if _, err := f.w.RecordPlayStarted(context.Background(), f.user, f.track, "c", t2); err != nil {
+		t.Fatalf("second: %v", err)
+	}
+	prior, _ := f.q.GetPlayEventByID(context.Background(), first.PlayEventID)
+	if !prior.WasSkipped {
+		t.Errorf("auto-close at 5s should be was_skipped=true")
+	}
+}
+
 func TestRecordPlayStarted_AutoCloseCapsAtTrackDuration(t *testing.T) {
 	f := newFixture(t, 60_000) // 60s track
 	t1 := time.Now().UTC()