docs(use-cases): a video track is accepted and the user is told; no-audio is rejected

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

docs/use-cases/audio_upload.feature

@@ -7,7 +7,9 @@ Feature: Upload an audio recording, get a private Swedish transcript, discuss it
   # PRIVATE content, so it lives in its own RLS-scoped store and never in the
   # shared public-caption `transcripts` table (ADR-021). Rejection is synchronous,
   # the audio is never retained, and a failed job ends in a terminal state with a
-  # message — never a spinner (ADR-025). Audio only: video is #28.
+  # message — never a spinner (ADR-025). A file with a video track (a Teams meeting
+  # with the camera off is one) is accepted: only its audio is used and the user is
+  # told. Video playback, keyframes and analysis of what is shown remain #28.
 
   Background:
     Given I am a registered user with audio upload enabled
@@ -25,9 +27,15 @@ Feature: Upload an audio recording, get a private Swedish transcript, discuss it
     When I upload an audio file and give no title
     Then its title is the filename without its extension
 
-  Scenario: A file containing video is rejected, naming issue 28
-    When I upload a file that has a video track
-    Then it is rejected with a message that video is tracked in issue 28
+  Scenario: A file with a video track is accepted and I am told the video was ignored
+    When I upload a recording that also has a video track
+    Then it is accepted and queued like any other
+    And its page says only its audio was used and the video was discarded
+    And it says so while queued, while transcribing, when done and when failed
+
+  Scenario: A video file with no audio is rejected for having no audio
+    When I upload a video that has no audio track
+    Then it is rejected with a message that it has no audio
     And nothing is recorded
 
   Scenario: A recording over the length limit is rejected with both lengths
@@ -40,10 +48,9 @@ Feature: Upload an audio recording, get a private Swedish transcript, discuss it
     Then it is rejected with 413 and a message about the limit
     And nothing is recorded
 
-  Scenario: An audio-only MP4 is not mistaken for video
-    When I upload an mp4 container that has an audio stream and no video stream
-    Then it is accepted
-    And an mp3 whose only video stream is cover art is accepted too
+  Scenario: Cover art on an audio file is not a video track
+    When I upload an mp3 whose only video stream is attached cover art
+    Then it is treated as audio and no video notice is shown
 
   Scenario: A file that is not media is rejected as unreadable
     When I upload a file ffprobe cannot read