Expand README with comprehensive documentation

[Copilot]

The README lacked depth and coverage of key features, making it difficult for users to understand capabilities and resolve common issues.

Changes

Structure & Navigation

• Added table of contents with anchor links to all major sections
• Organized content into 15 major sections from original 3

Content Additions

• Quick Start: Working example covering basic upload/read/delete operations
• Configuration: Detailed options including overwrite behavior, delete options, and path converters
• Usage Examples: File operations, directory listing, metadata retrieval, and stream handling
• Advanced Features: Complete documentation of transformations, custom path converters, and all three plugins (GetUrl, ReadTransformation, GetVersionedUrl)
• API Reference: Method signatures for CloudinaryAdapter and ApiFacade
• Troubleshooting: Common issues (double extensions, folder creation, authentication) with solutions
• Cloudinary Behaviors: Platform-specific quirks (auto-appended extensions, no empty folders, video file handling)

Example - Transformation Usage (previously undocumented in README):

use Enl\Flysystem\Cloudinary\Plugin\GetUrl;

$filesystem->addPlugin(new GetUrl($client));
$url = $filesystem->getUrl('image.jpg', [
    'width' => 600,
    'height' => 400,
    'crop' => 'fill',
    'gravity' => 'face'
]);

Increased from 58 to 633 lines. All internal documentation links verified.

Original prompt

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This section details on the original issue you should resolve

<issue_title>update readme to make it more detailed</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes update readme to make it more detailed #6

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