🌎 i18n: React-i18next & i18next Integration (#5720)

* better i18n support an internationalization-framework.

* removed unused package

* auto sort for translation.json

* fixed tests with the new locales function

* added new CI actions from locize

* to use locize a mention in the README.md

* to use locize a mention in the README.md

* updated README.md and added TRANSLATION.md to the repo

* updated TRANSLATION.md badges

* updated README.md to go to the TRANSLATION.md when clicking on the Translation Progress badge

* updated TRANSLATION.md and added a new issue template.

* updated TRANSLATION.md and added a new issue template.

* updated issue template to add the iso code link.

* updated the new GitHub actions for `locize`

* updated label for new issue template --> i18n

* fixed type issue

* Fix eslint

* Fix eslint with key-spacing spacing

* fix: error type

* fix: handle undefined values in SortFilterHeader component

* fix: typing in Image component

* fix: handle optional promptGroup in PromptCard component

* fix: update localize function to accept string type and remove unnecessary JSX element

* fix: update localize function to enforce TranslationKeys type for better type safety

* fix: improve type safety and handle null values in Assistants component

* fix: enhance null checks for fileId in FilesListView component

* fix: localize 'Go back' button text in FilesListView component

* fix: update aria-label for menu buttons and add translation for 'Close Menu'

* docs: add Reasoning UI section for Chain-of-Thought AI models in README

* fix: enhance type safety by adding type for message in MultiMessage component

* fix: improve null checks and optional chaining in useAutoSave hook

* fix: improve handling of optional properties in cleanupPreset function

* fix: ensure isFetchingNextPage defaults to false and improve null checks for messages in Search component

* fix: enhance type safety and null checks in useBuildMessageTree hook

---------

Co-authored-by: Danny Avila <danny@librechat.ai>

README.md

@@ -38,6 +38,15 @@
 </a>
 </p>
 
+<p align="center">
+  <a href=https://github.com/danny-avila/LibreChat/blob/main/.github/TRANSLATION.md">
+    <img 
+      src="https://img.shields.io/badge/dynamic/json.svg?style=for-the-badge&color=2096F3&label=locize&query=%24.translatedPercentage&url=https://api.locize.app/badgedata/4cb2598b-ed4d-469c-9b04-2ed531a8cb45&suffix=%+translated" 
+      alt="Translation Progress">
+  </a>
+</p>
+
+
 # ✨ Features
 
 - 🖥️ **UI & Experience** inspired by ChatGPT with enhanced design and features
@@ -79,6 +88,9 @@
   - English, 中文, Deutsch, Español, Français, Italiano, Polski, Português Brasileiro
   - Русский, 日本語, Svenska, 한국어, Tiếng Việt, 繁體中文, العربية, Türkçe, Nederlands, עברית
 
+- 🧠 **Reasoning UI**:  
+  - Dynamic Reasoning UI for Chain-of-Thought/Reasoning AI models like DeepSeek-R1
+
 - 🎨 **Customizable Interface**:  
   - Customizable Dropdown & Interface that adapts to both power users and newcomers
 
@@ -167,6 +179,8 @@ Contributions, suggestions, bug reports and fixes are welcome!
 
 For new features, components, or extensions, please open an issue and discuss before sending a PR.
 
+If you'd like to help translate LibreChat into your language, we'd love your contribution! Improving our translations not only makes LibreChat more accessible to users around the world but also enhances the overall user experience. Please check out our [Translation Guide](.github/TRANSLATION.md).
+
 ---
 
 ## 💖 This project exists in its current state thanks to all the people who contribute
@@ -174,3 +188,15 @@ For new features, components, or extensions, please open an issue and discuss be
 <a href="https://github.com/danny-avila/LibreChat/graphs/contributors">
   <img src="https://contrib.rocks/image?repo=danny-avila/LibreChat" />
 </a>
+
+---
+
+## 🎉 Special Thanks
+
+We thank [Locize](https://locize.com) for their translation management tools that support multiple languages in LibreChat.
+
+<p align="center">
+  <a href="https://locize.com" target="_blank" rel="noopener noreferrer">
+    <img src="https://locize.com/img/locize_color.svg" alt="Locize Logo" height="50">
+  </a>
+</p>