Add tiered summarization based on pricing plans

- Implement advanced AI summarization with action items for Pro plan
- Create basic bullet-point summarization for Freemium plan
- Add plan tier validation and feature differentiation
- Support speaker identification in transcripts
- Define plan limits (600 mins Pro/200 mins Freemium)

requirements.txt

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+openai
+pandas
+python-dotenv
+fastapi
+uvicorn
+langchain-community
+langchain-openai
+pydantic
+pypdf
+pypandoc
+Spire.Doc
+plum-dispatch==1.7.4
+scikit-learn
+werkzeug
+python-multipart
+langgraph
+tiktoken
+langchainhub
+chromadb
+langchain
+langchain-text-splitters
+beautifulsoup4
+deepgram_sdk
+moviepy
+yt-dlp
+ffmpeg-python
+reportlab
+anthropic