docs(i18n): add Greek translations (#2985)

* docs(i18n): add Greek translations

Give Greek-speaking readers localized onboarding guidance and begin website coverage while keeping incomplete pages on the explicit English fallback.

- Add the reviewed Greek README and place Greek last in every language selector.
- Register Greek website localization and include 206 translated messages.
- Keep incomplete routes nonindexable and replace fixed translation counts with inventory-based coverage.

Refs #2984

* docs(website): improve Greek homepage wording

docs/readme/README_pl.md

@@ -1,6 +1,7 @@
 <div align="center">
 
 [English](../../README.md) · [简体中文](README_zh.md) · [繁體中文](README_zh-TW.md) · [日本語](README_ja.md) · [한국어](README_ko.md) · [Türkçe](README_tr.md) · [Русский](README_ru.md) · [Tiếng Việt](README_vi.md) · [ไทย](README_th.md) · [Deutsch](README_de.md) · [Español](README_es.md) · [Français](README_fr.md) · [Українська](README_uk.md) · **Polski** · [Português (Brasil)](README_pt-BR.md) · [العربية](README_ar.md) · [فارسی](README_fa.md) · [Bahasa Indonesia](README_id.md) · [Italiano](README_it.md)
+· [Ελληνικά](README_el.md)
 
 # REA: Reverse Engineer Anything