update app.py for gradio 6 compat

app.py

@@ -31,11 +31,13 @@ def synthesize_speech(text):
     buffer.seek(0)
     audio_data = np.frombuffer(buffer.read(), dtype=np.int16)
 
-    return audio_data.tobytes(), None
+    # In Gradio 6, Audio with type="numpy" expects a tuple of (sample_rate, audio_array)
+    return (voice.config.sample_rate, audio_data), None
 
 
 # Using Gradio Blocks
-with gr.Blocks(theme=gr.themes.Base()) as blocks:
+# In Gradio 6, theme moved from Blocks() constructor to launch()
+with gr.Blocks() as blocks:
     gr.Markdown("# Text to Speech Synthesizer")
     gr.Markdown("Enter text to synthesize it into speech using PiperVoice.")
     input_text = gr.Textbox(label="Input Text")
@@ -50,4 +52,4 @@ with gr.Blocks(theme=gr.themes.Base()) as blocks:
     )
 
 # Run the app
-blocks.launch()
+blocks.launch(theme="base")