feat: support multi-character aliases

[boneskull]

• Register multi-char aliases as separate options with parseArgs()
• Collapse alias values into canonical names after parsing
• Detect conflicts when both alias and canonical provided for non-array options
• Merge values for array options when both alias and canonical provided
• Validate aliases don't conflict with canonical option names
• Validate aliases don't conflict with auto-generated boolean negations
• Display multi-character aliases in help output
• Update README.md documentation with aliases section

[boneskull]

• feat: support multi-character aliases #19 👈 (View in Graphite)
• main

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[Copilot]

Pull request overview

This PR adds support for multi-character aliases for CLI options, expanding beyond the previous single-character limitation. The implementation registers multi-character aliases as separate options in Node.js parseArgs(), then collapses them back to canonical names after parsing.

Key changes:

• Multi-character aliases are now validated and supported alongside single-character aliases
• Conflict detection ensures aliases don't collide with option names or auto-generated boolean negations
• Array options merge values from all aliases; non-array options detect conflicts when both alias and canonical are used
• Help text displays multi-character aliases sorted by length

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/validate.ts	Added validation to check aliases against canonical names and boolean negations; removed single-character restriction
src/parser.ts	Implemented collapseAliases() function to merge multi-char alias values into canonical names; registers multi-char aliases as separate parseArgs options
src/opt.ts	Enhanced alias conflict validation to check against canonical names and boolean negations
src/help.ts	Updated help formatting to display multi-character aliases sorted by length alongside short aliases
src/types.ts	Updated documentation for the aliases property to describe both short and long alias support
test/validate.test.ts	Added comprehensive tests for multi-char alias validation, conflicts, and error cases
test/parser.test.ts	Added tests for parsing multi-char aliases, conflict detection, and array value merging
test/opt.test.ts	Added tests for alias conflict detection in the opt builder API
test/help.test.ts	Added tests to verify multi-char aliases appear correctly in help output
README.md	Added dedicated "Aliases" section with examples of short and long alias usage, conflict behavior, and array merging

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