refactor: Replace hardcoded model names with dynamic model selection

app.py

@@ -340,14 +340,14 @@ with gr.Blocks() as demo:
                     "Use the image as the background with a waveform visualization for the audio positioned in center of the video.",
                     0.7,
                     0.1,
-                    "Qwen/Qwen2.5-Coder-32B-Instruct",
+                    list(MODELS.keys())[0],
                 ],
                 [
                     ["./examples/ai_talk.wav", "./examples/bg-image.png"],
                     "Use the image as the background with a waveform visualization for the audio positioned in center of the video. Make sure the waveform has a max height of 250 pixels.",
                     0.7,
                     0.1,
-                    "deepseek-ai/DeepSeek-V3",
+                    list(MODELS.keys())[0],
                 ],
                 [
                     [
@@ -362,7 +362,7 @@ with gr.Blocks() as demo:
                     "Create a 3x2 grid of the cat images with the audio as background music. Make the video duration match the audio duration.",
                     0.7,
                     0.1,
-                    "deepseek-ai/DeepSeek-V3",
+                    list(MODELS.keys())[0],
                 ],
             ],
             inputs=[user_files, user_prompt, top_p, temperature, model_choice],