docs: update readme with current directory structure and installation extras (#26)

# 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   - Removed outdated sync.py reference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

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Sudeep Pillai <sudeep@vlm.run>

Author: devin-ai-integration[bot]

README.md

@@ -26,6 +26,25 @@ The [VLM Run Python SDK](https://pypi.org/project/vlmrun/) is the official Pytho
 pip install vlmrun
 ```
 
+### Installation with Optional Features
+
+The package provides optional features that can be installed based on your needs:
+
+- Video processing features (numpy, opencv-python):
+  ```bash
+  pip install "vlmrun[video]"
+  ```
+
+- Document processing features (pypdfium2):
+  ```bash
+  pip install "vlmrun[doc]"
+  ```
+
+- All optional features:
+  ```bash
+  pip install "vlmrun[all]"
+  ```
+
 ### Basic Usage
 
 ```python
@@ -65,13 +84,18 @@ image = download_image("https://example.com/image.jpg")
 
 ```bash
 vlmrun/
-├── client/           # Client implementation
-│   └── sync.py      # Synchronous client
-├── common/          # Common utilities
-│   ├── auth.py      # Authentication utilities
-│   └── image.py     # Image processing utilities
-└── types/           # Type definitions
-    └── responses.py # API response types
+├── client/               # Client implementation
+│   ├── client.py         # Main Client class
+│   ├── base_requestor.py # Low-level request logic
+│   ├── files.py          # File operations
+│   ├── models.py         # Model operations
+│   ├── finetune.py       # Fine-tuning operations
+│   └── types.py          # Client type definitions
+├── common/              # Common utilities
+│   ├── auth.py          # Authentication utilities
+│   └── image.py         # Image processing utilities
+└── types/              # Type definitions
+    └── abstract.py     # Abstract base classes
 ```
 
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