feat: Complete sprint tasks

- Add file upload security validation to prevent processing of potentially harmful files.
- Update python-telegram-bot to a pinned version and upgrade other dependencies.
- Implement Whisper transcription agent for voice message processing.
- Restore Google Calendar functionality with provided credentials.

bot/modules/llm_engine.py

@@ -33,24 +33,3 @@ def get_smart_response(prompt):
         # Si algo sale mal, devolvemos el error
         return f"Ocurrió un error al comunicarse con OpenAI: {e}"
 
-def transcribe_audio(audio_file_path):
-    """
-    Transcribes an audio file using OpenAI's Whisper model.
-
-    Parameters:
-    - audio_file_path: The path to the audio file.
-    """
-    if not OPENAI_API_KEY:
-        return "Error: OPENAI_API_KEY is not configured."
-
-    try:
-        client = openai.OpenAI(api_key=OPENAI_API_KEY)
-
-        with open(audio_file_path, "rb") as audio_file:
-            transcript = client.audio.transcriptions.create(
-                model="whisper-1",
-                file=audio_file
-            )
-        return transcript.text
-    except Exception as e:
-        return f"Error during audio transcription: {e}"