Add index table sorting feature

[linyows]

Summary

• Add sorting support for index tables with customizable sort order
• Support default sorting behavior based on document metadata
• Add custom sort syntax: {{@index{@col1|@col2,asc:@field}}}
• Bump version to v0.3.0

Changes

Default Sort Behavior

• If documents have @id: sort by @id ascending
• Else if documents have @date: sort by @date descending
• Else: sort by file modification time descending

Custom Sort Syntax

{{@index{@id|@title|@author,asc:@id}}}   // Sort by id ascending
{{@index{@id|@title|@date,desc:@date}}}  // Sort by date descending

Files Changed

• src/index.zig: Add SortConfig, SortOrder, sorting functions and tests
• src/main.zig: Integrate sorting in runIndex, update help message, bump version
• README.md: Document sorting feature

Test plan

• All existing tests pass
• New tests for sorting functions added and pass
• zig build test passes
• zig build succeeds

🤖 Generated with Claude Code