(feat): Add support for batch file reading in fs_read tool

[evanliu048]

Issue #, if available:

Description of changes:
Enhanced the fs_read tool to support batch operations, allowing multiple file/directory operations in a single command while maintaining backward compatibility.

Changes

1. Core Structure Updates:

• Modified FsRead struct to support batch operations via operations: Option<Vec<FsReadOperation>>
• Added optional summary field for better UX when describing batch operations
• Maintained backward compatibility for single operations

2. Mixed Output Support

• Added OutputKind::Mixed { text: String, images: RichImageBlocks } variant to handle operations that return both text and images
• Ensures all operation results (text and images) are properly passed to the model
• Fixed issue where batch operations with images would lose text results

3. fs_read JSON Schema Updates Updated

{
  "operations": [{
    "mode": "Line|Directory|Search|Image",
    "path": "...",
    // mode-specific parameters
  }],
  "purpose": "optional description"
}

Experience

Screen.Recording.2025-07-01.at.10.18.33.AM.mov

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