test(web): match the notice's real casing

My assertion expected a lowercase 'only'; the sentence begins 'Only'. The user
facing wording is unchanged.

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

internal/web/uploads_handler_test.go

@@ -322,7 +322,7 @@ func TestUploadStatus_TellsTheUserTheVideoWasIgnoredInEveryStateAndOnlyWhenItWas
 			plain := body(t, do(t, app, get("/uploads/"+audioOnly+"/status")))
 
 			assert.Contains(t, notice, "video track")
-			assert.Contains(t, notice, "only its audio was used", "say what happened, not just that something did")
+			assert.Contains(t, notice, "Only its audio was used", "say what happened, not just that something did")
 			assert.Contains(t, notice, "discarded")
 			assert.NotContains(t, plain, "video track", "no notice when there was no video")
 		})
@@ -334,5 +334,5 @@ func TestUploadPage_AlsoCarriesTheVideoNotice(t *testing.T) {
 	id := seedUpload(t, userID, "camera off", "done", "Synthetic transcript.")
 	markHadVideo(t, id)
 
-	assert.Contains(t, body(t, do(t, app, get("/uploads/"+id))), "only its audio was used")
+	assert.Contains(t, body(t, do(t, app, get("/uploads/"+id))), "Only its audio was used")
 }