feat: support uploaded images in debug voice preview

Allow paste/drag temporary image assets so vision turns work without a live camera frame.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/services/pipecat/pipeline_events.py

@@ -149,11 +149,12 @@ def bind_cascade_pipeline_events(
 
     @text_input.event_handler("on_user_input")
     async def on_user_input(_processor, user_input: UserInput):
-        await queue_transcript(
-            "user",
-            user_input.transcript_text,
-            time_now_iso8601(),
-        )
+        if not user_input.has_image:
+            await queue_transcript(
+                "user",
+                user_input.transcript_text,
+                time_now_iso8601(),
+            )
         if user_input.run_immediately and user_input.interrupt:
             pending_user_inputs.append(user_input)
             return