[tools] Add optimize_style_tool for style optimization

[mattpodwysocki]

Summary

Implements a comprehensive style optimization tool that reduces Mapbox style file size and improves performance by removing redundancies and simplifying structure.

Key Features

• Remove Unused Sources: Identifies and removes source definitions not referenced by any layer
• Remove Duplicate Layers: Detects layers with identical properties (excluding ID) and removes duplicates
• Simplify Expressions: Simplifies boolean logic in filters and paint/layout properties
• Remove Empty Layers: Removes layers with no visible properties (preserves background layers)
• Identify Consolidation Opportunities: Finds layers with identical filter expressions

Implementation Details

• Extends BaseTool for offline operation (no API calls required)
• Performs deep analysis of style JSON structure
• Tracks all optimizations with detailed descriptions
• Calculates size savings and percentage reduction
• Selective optimization: Apply specific optimizations or all at once
• Full Zod schema validation for inputs and outputs

Optimizations

Remove Unused Sources

Scans all layers to identify which sources are referenced, then removes any sources not in use.

Remove Duplicate Layers

Compares layers excluding their ID to find exact duplicates and removes them.

Simplify Expressions

Simplifies boolean expressions in filters and properties:

• ["all", true] → true
• ["any", false] → false
• ["!", false] → true
• ["!", true] → false

Remove Empty Layers

Removes layers with no paint or layout properties (background layers are preserved since they're valid even when empty).

Consolidate Filters

Identifies groups of layers with identical filter expressions that could potentially be consolidated.

Testing

• 21 comprehensive test cases covering:
  • Tool metadata validation
  • Basic optimization with JSON string/object input
  • Remove unused sources (with/without unused sources)
  • Remove duplicate layers (with/without duplicates)
  • Simplify expressions (all simplification rules)
  • Remove empty layers (preserving background layers)
  • Consolidate filters identification
  • Combined optimizations
  • Summary statistics (size savings, percent reduction)
  • Error handling (invalid JSON)
  • Already-optimized styles (zero optimizations)

All tests passing ✅

Documentation

Added comprehensive README documentation with:

• Parameters and options
• Description of all optimization types
• Return value structure with example JSON
• Example prompts for users

Use Cases

This tool enables:

• Reducing style file size for faster loading
• Cleaning up styles after multiple edits/iterations
• Identifying optimization opportunities
• Preparing styles for production deployment
• Understanding style complexity through size metrics

Related PRs

Completes the offline validation tools initiative:

• Add validate_style_tool for offline Mapbox style validation #49 - validate_style_tool (merged)
• Add validate_geojson_tool for offline GeoJSON validation #50 - validate_geojson_tool (in review)
• Add validate_expression_tool for Mapbox expression validation #51 - validate_expression_tool (in review)
• [tools] Add compare_styles_tool for style comparison #52 - compare_styles_tool (in review)
• [tools] Add check_color_contrast_tool for WCAG accessibility compliance #53 - check_color_contrast_tool (in review)
• This PR - optimize_style_tool

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