test(audio): opt-in live ffprobe check on hostile playlists and real audio

Skipped unless TAPIR_LIVE_FFPROBE is set. Synthetic/crafted files only.

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

internal/adapters/audio/hostile_live_test.go

@@ -0,0 +1,32 @@
+package audio_test
+
+import (
+	"context"
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"git.d-ma.be/mathias/tapir/internal/adapters/audio"
+	"git.d-ma.be/mathias/tapir/internal/uploads"
+)
+
+// TestFFprobeLive_HostilePlaylistsAreRefusedAndRealAudioIsNot runs the REAL ffprobe
+// (opt-in: TAPIR_LIVE_FFPROBE) on crafted concat/HLS files and on a real m4a.
+func TestFFprobeLive_HostilePlaylistsAreRefusedAndRealAudioIsNot(t *testing.T) {
+	bin := os.Getenv("TAPIR_LIVE_FFPROBE")
+	if bin == "" {
+		t.Skip("set TAPIR_LIVE_FFPROBE (and TAPIR_LIVE_HOSTILE_DIR, TAPIR_LIVE_M4A) to run against the real ffprobe")
+	}
+	p := &audio.FFprobe{Bin: bin}
+	for _, name := range []string{"up-concat", "up-hls"} {
+		_, err := p.Probe(context.Background(), os.Getenv("TAPIR_LIVE_HOSTILE_DIR")+"/"+name)
+		assert.ErrorIs(t, err, uploads.ErrUnreadable, name)
+	}
+	got, err := p.Probe(context.Background(), os.Getenv("TAPIR_LIVE_M4A"))
+	require.NoError(t, err)
+	assert.True(t, got.HasAudio)
+	assert.False(t, got.HasVideo)
+	assert.InDelta(t, 82.5, got.Duration.Seconds(), 1)
+}