Merge multiple SVG paths into single paths for outline icons

Fixes issue reported here: #1392

Summary

• Merged multiple SVG paths into single paths for all icons in icons/outline/ directory
• Optimized ~3,000+ multi-path SVG files by concatenating their d attributes
• Preserved all metadata, comments, and SVG structure - only path elements were modified
• Updated the build pipeline (optimize.mjs) to automatically merge paths for all future icons

Changes

1. Batch Processing of Existing Icons

Merged paths for all existing multi-path SVG files using a custom script. For example:

Before:

<path d="M3 16v-5.5a2.5 2.5 0 0 1 5 0v5.5m0 -4h-5" />
<path d="M12 6l0 12" />
<path d="M16 16v-8h3a2 2 0 0 1 0 4h-3m3 0a2 2 0 0 1 0 4h-3" />

After:

<path d="M3 16v-5.5a2.5 2.5 0 0 1 5 0v5.5m0 -4h-5M12 6l0 12M16 16v-8h3a2 2 0 0 1 0 4h-3m3 0a2 2 0 0 1 0 4h-3" />

2. Build Pipeline Enhancement

Modified .build/optimize.mjs to automatically merge paths during the optimization process, ensuring:

• All future icons will have merged paths
• Consistency across the entire icon library
• Integration with the existing build workflow

Benefits

• Reduced file size: Fewer elements and less markup
• Improved rendering performance: Single path rendering is more efficient than multiple paths
• Cleaner SVG structure: Simplified DOM tree for each icon
• Future-proof: All new icons automatically get optimized
• No visual changes: Icons render identically to their original versions

Testing

• Verified all icons render correctly after path merging
• Confirmed metadata and comments are preserved
• Validated SVG syntax remains valid
• Tested the modified build script (optimize.mjs)
• Verified path merging works for new icons added to the project
• Tested in multiple browsers for compatibility

Files Changed

• 4,803 SVG files in icons with merged paths
• .build/optimize.mjs - Added path merging logic to the build pipeline