Fixes #5169: Add image reading support to read_file tool

[roomote]

This PR implements image reading support for the read_file tool as requested in issue #5169.

Changes

• Extended FileResult interface to include imageData and mimeType fields
• Added helper functions for image detection, MIME type determination, and base64 conversion
• Implemented size validation with 10MB limit to prevent memory issues
• Added support for PNG, JPG, JPEG, WebP, GIF, BMP, ICO, TIFF, SVG formats
• Updated binary file handling logic to detect and process image files
• Created comprehensive test suite covering all formats and edge cases

Technical Details

• Uses file extension matching to identify supported image formats
• Converts images to base64 format for transmission with proper MIME types
• Validates file size before processing to prevent memory issues
• Maintains backward compatibility with existing functionality
• Proper error handling for unsupported formats and oversized files

Testing

• Added comprehensive test suite in readFileTool.image.spec.ts
• Tests cover all supported formats, error handling, size limits
• All existing tests continue to pass

Closes #5169

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Important

Adds image reading support to readFileTool with base64 conversion, size validation, and comprehensive testing.

• Behavior:
  • Adds image reading support to readFileTool for PNG, JPG, JPEG, WebP, GIF, BMP, ICO, TIFF, SVG formats.
  • Converts images to base64 with MIME type for transmission.
  • Implements size validation with a 10MB limit in readFileTool.ts.
  • Handles unsupported formats and oversized files with error messages.
• Functions:
  • Adds isSupportedImageFile(), getImageMimeType(), and readImageAsBase64() to readFileTool.ts.
  • Extends FileResult interface with imageData and mimeType fields.
• Testing:
  • Adds readFileTool.image.spec.ts with tests for all supported formats, error handling, and size limits.

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[delve-auditor]

✅ No security or compliance issues detected. Reviewed everything up to 8bdd350.

Security Overview

• 🔎 Scanned files: 2 changed file(s)

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