task: add CHANGELOG, LLMS docs, and enhance type definitions

[bombillazo]

Summary

• Add CHANGELOG.md documenting full version history from 0.1.0 to 0.6.0
• Add LLMS.md with AI-friendly documentation containing usage examples and API reference
• Enhance JSDoc documentation across resolver and preset modules with @example tags
• Add .gitattributes for custom merge strategy on JSONL files

Test plan

• Verify pnpm typecheck passes
• Verify pnpm lint passes
• Verify pnpm test passes
• Review CHANGELOG.md follows Keep a Changelog format
• Review LLMS.md examples are accurate and runnable

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Adds project documentation artifacts (CHANGELOG + AI-friendly docs) and expands JSDoc/module documentation around the public API, plus some repo-level git configuration updates.

Changes:

• Add CHANGELOG.md with version history entries and compare links.
• Add LLMS.md with usage examples and a consolidated API/type reference.
• Expand module/JSDoc documentation in type and preset entrypoints and in ErrorXResolver, and add git ignore/attributes entries.

Reviewed changes

Copilot reviewed 7 out of 8 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
src/types/index.ts	Adds module/package documentation for exported type groups.
src/resolver.ts	Enhances JSDoc for resolver internals with clearer behavior notes and examples.
src/presets/index.ts	Adds module/package docs describing preset error exports and usage examples.
LLMS.md	Introduces an AI-friendly usage/API reference document.
CHANGELOG.md	Introduces a Keep a Changelog formatted changelog with historical entries.
.gitignore	Ignores additional local/dev-tool artifacts.
.gitattributes	Adds a custom merge attribute targeting a JSONL file path.

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