# Contributing

Contributions are welcome when they preserve the application's local-first,
inspection-oriented boundary.

## Development workflow

1. Use Node.js 22 or newer.
2. Install the locked dependencies with `npm ci`.
3. Keep parsing, package traversal and expensive work away from the React render
   path; use bounded worker operations where appropriate.
4. Add focused unit tests and malformed-input cases for every parser change.
5. Run `npm run check` and `npm run test:browser` before proposing a change.

Do not add telemetry, remote document conversion, runtime CDN dependencies or
automatic external-resource fetching. Never execute macros, embedded scripts or
active document content. New dependencies need a licence and maintenance review
and must be reflected in `THIRD_PARTY_NOTICES.md` where required.

Format support must be described conservatively. A partial reader should expose
what it preserved, approximated, omitted or rejected rather than claiming Office
suite fidelity.

By contributing, you agree that your contribution is licensed under
GPL-3.0-or-later.