#3355 [Docs] add Polish README translation

Descrição

## Problem and result

README was missing a Polish version. This change adds a Polish translation aligned with the repository's 0.2.0-beta README and adds the Polish language link to all existing README language selectors.

## Related discussion

Replacement for [#2949](https://github.com/Niko1221/Strata/pull/2949). Its /reopen check passed, but GitHub could not reopen that closed pull request.

## Approach

Translated the current installation, model, usage, performance, troubleshooting, and contribution guidance. No runtime code or defaults changed.

## Validation

**Passed:**
- `git diff --check origin/main...0700f56f745ab41278484b13f175dd3677cb6290` — clean on Linux, rebased on `main` at `e88ee39d` (0.2.0-beta).
- Inline Python 3 standard-library check — local link targets across all eight README files, Polish links in the seven existing locale selectors, and the beta version and CLI example passed on revision `0700f56f`.

**Failed:** None observed.

**Not run:** Runtime tests and GPU builds; this is a documentation-only change.

## Limits

This change updates the documentation only.