♻️(backend) encapsulate recording key and extension logic as properties

Move logic for calculating recording keys and file extensions into proper
properties on recording objects. Simplifies access to Minio storage keys
and clearly documents expected behavior when saving recordings across the
application.

src/backend/core/tests/test_models_recording.py

@@ -12,7 +12,8 @@ from core.factories import (
     UserFactory,
     UserRecordingAccessFactory,
 )
-from core.models import Recording, RecordingStatusChoices
+from core.models import Recording, RecordingModeChoices, RecordingStatusChoices
+from core.recording.enums import FileExtension
 
 pytestmark = pytest.mark.django_db
 
@@ -216,3 +217,36 @@ def test_models_recording_worker_id_very_long():
     too_long_id = "w" * 256
     with pytest.raises(ValidationError):
         RecordingFactory(worker_id=too_long_id)
+
+
+# Test key property method
+
+
+def test_models_recording_key_for_transcript(settings):
+    """Test key property returns correct path for transcript mode."""
+
+    settings.RECORDING_OUTPUT_FOLDER = "/custom/path"
+
+    recording = RecordingFactory(mode=RecordingModeChoices.TRANSCRIPT)
+    expected_path = f"/custom/path/{recording.id}.{FileExtension.OGG.value}"
+    assert recording.key == expected_path
+
+
+def test_models_recording_key_for_screen_recording(settings):
+    """Test key property returns correct path for screen recording mode."""
+    settings.RECORDING_OUTPUT_FOLDER = "/custom/path"
+
+    recording = RecordingFactory(mode=RecordingModeChoices.SCREEN_RECORDING)
+    expected_path = f"/custom/path/{recording.id}.{FileExtension.MP4.value}"
+    assert recording.key == expected_path
+
+
+def test_models_recording_key_for_unknown_mode(settings):
+    """Test key property uses default extension for unknown mode."""
+
+    settings.RECORDING_OUTPUT_FOLDER = "/custom/path"
+    recording = RecordingFactory()
+    # Directly set an invalid mode (bypassing validation)
+    recording.mode = "unknown_mode"
+    expected_path = f"/custom/path/{recording.id}.{FileExtension.MP4.value}"
+    assert recording.key == expected_path