feat: add heal cut ffmpeg command

tests/test_utils.py

@@ -231,6 +231,42 @@ def test_audio_delete_empty_head():
     assert "atrim=end=0.0" in fc and "atrim=start=2.0" in fc
 
 
+def test_audio_heal_delete_command_crossfades_join():
+    from core.ffmpeg import build_audio_heal_delete_command
+    cmd = build_audio_heal_delete_command("/in.wav", 2.0, 4.0, "/o/o.wav", crossfade=0.1)
+    assert cmd[0] == "ffmpeg"
+    assert cmd.count("-i") == 1
+    fc = cmd[cmd.index("-filter_complex") + 1]
+    assert "atrim=end=2.0" in fc
+    assert "atrim=start=4.0" in fc
+    assert "acrossfade=d=0.1:c1=qsin:c2=qsin[out]" in fc
+    assert cmd[cmd.index("-map") + 1] == "[out]"
+    assert "pcm_s16le" in cmd
+    assert cmd[-1] == "/o/o.wav"
+
+
+def test_audio_heal_delete_command_auto_crossfade_clamped():
+    from core.ffmpeg import build_audio_heal_delete_command
+    cmd = build_audio_heal_delete_command("/in.wav", 10.0, 12.0, "/o/o.mp3")
+    fc = cmd[cmd.index("-filter_complex") + 1]
+    assert "acrossfade=d=0.25:c1=qsin:c2=qsin[out]" in fc
+    assert "libmp3lame" in cmd
+
+
+def test_audio_heal_delete_command_near_start_shortens_crossfade():
+    from core.ffmpeg import build_audio_heal_delete_command
+    cmd = build_audio_heal_delete_command("/in.wav", 0.03, 1.0, "/o/o.wav")
+    fc = cmd[cmd.index("-filter_complex") + 1]
+    assert "acrossfade=d=0.03:c1=qsin:c2=qsin[out]" in fc
+
+
+def test_audio_heal_delete_command_rejects_invalid_region():
+    import pytest
+    from core.ffmpeg import build_audio_heal_delete_command
+    with pytest.raises(ValueError):
+        build_audio_heal_delete_command("/in.wav", 3.0, 3.0, "/o/o.wav")
+
+
 # --- ProcessedDB ---
 
 def test_db_add_and_get_markers():