docs: update readme with current directory structure and installation extras

[devin-ai-integration]

Documentation Updates

This PR updates the README.md to accurately reflect the current state of the codebase:

Changes Made

1. Updated directory structure to show all current client files:

   • Added client.py (Main Client class)
   • Added base_requestor.py (Low-level request logic)
   • Added files.py (File operations)
   • Added models.py (Model operations)
   • Added finetune.py (Fine-tuning operations)
   • Added types.py (Client type definitions)
   • Removed outdated sync.py reference

2. Added installation extras documentation:

   • Video processing features (numpy, opencv-python)
   • Document processing features (pypdfium2)
   • All features combined option

3. Verified types/abstract.py usage:

   • Confirmed it's actively used by files.py, models.py, and finetune.py
   • Contains essential Client Protocol class
   • Kept in codebase as it's required

4. Confirmed Discord URL consistency:

   • All Discord links consistently use discord.gg/AMApC2UzVY
   • No inconsistencies found

Testing

Documentation-only changes, no code modifications required.

Link to Devin run: https://app.devin.ai/sessions/f6485ae88e814f8fae7998b7c2622f81

[devin-ai-integration]

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